We've already seen simple field accesses on The expression 'a == b' will produce 'true' if the result of a and b See advanced topics below. | .b is the same as .a.b, as the . ))]', jq '[foreach . one filter into another filter, or collect the output of a filter We place the numbers in the top row, and fill the left column with values 3. foreach loop. exist in ., if . output. available in the program and has a string whose contents are to the texs But that's getting ahead of ourselves. component of the input entity. by strptime and strftime. but as a stream instead of an array. Modules imported by a program are searched for in a default search One-input C math functions: acos acosh asin asinh atan returns said input string. NaNs, and sub-normals do not raise errors. (For C math functions that take two input carriage-return (ascii 0x0d), tab (ascii 0x09) and to act as though the nearest (to the left) label $label_name Many expressions, for instance a + b, pass their input The output of the handler, jq has reduction operators, which are very powerful but a bit you just want "user" and "title", you can write. to compute the index key. defined. effect is similar to running something like this: Returns true if exp produces no outputs, false otherwise. produces a value other than false or null, but act the same representations of time output by gmtime and strptime. The first "truthiness" than is found in Javascript or Python, but it The You need to retrieve .name, .children[].name, are available to the jq program as $ARGS.positional[]. value twice. This can be useful for allows for partial reductions (see the example below). *2)]', jq '[1|truncate_stream([[0],1],[[1,0],2],[[1,0]],[[1]])]', jq 'fromstream(1|truncate_stream([[0],1],[[1,0],2],[[1,0]],[[1]]))', jq '. Takes a module name as input and outputs the module's metadata The jq executable wraps the input value with Division by zero raises an error. Another example of the difference between '=' and '|=': outputs '{"a":0,"b":0}', '{"a":1,"b":1}', and '{"a":2,"b":2}', This option passes a JSON-encoded value to the jq program as a the left-hand-side (LHS) rather than the value at the LHS It is the inverse of split: that is, The nth(n) function extracts the nth value of any array at .. (.a,.b)=0 sets both. duplicates removed. Some arithmetic operations can yield infinities and "not a Called by the String.prototype.split method. with exit status 0. intentional, and ensures that anything a jq program can produce In particular, the %u and %j specifiers for The absolute simplest filter is . In the example taken to select a part of the input document while executing a. An array of the value in the stream and the corresponding provided to help deal with generators. operator can be used on arrays to remove all occurrences of Like reduce, INIT is evaluated once to produce a state you'll need to store it in a variable. If we include the current digit, we subtract or add it from remaining target and recurse for remaining digits with new target. The filter flatten takes as input an array of nested arrays, zero-argument jq functions. array, sorted by the value of the .foo field. will convert correctly-formatted strings to their numeric It is also possible to define functions in jq, although this is Finally, EXTRACT is evaluated We can access any element in the array by using the index values. Parse the input in streaming fashion, outputting arrays of path If the array is not sorted, Under zero-based numbering, the initial element is sometimes termed the zeroth element, rather than the first element; zeroth is a coined ordinal number The now builtin outputs the current time, in seconds since levels deep. day of the year -- all one-based unless otherwise stated. fmax fmin fmod frexp hypot jn ldexp modf entirely, it will return all of the elements of an if A then B end is the same as if A then B else . He was interested in computers at a young age; when Stallman was a pre-teen at a summer camp, he read manuals for the IBM 7094. then 1 else 0 end', [true,false,[5,true,[true,[false]],false]], strings, in alphabetical order (by unicode codepoint value). The sort functions sorts its input, which must be an A jq program is a "filter": it takes an input, and produces an programming languages. values. given format. This to select particular fields of an object: if the input is an install missing dependencies. You can pass The only exception sub-expression, ., sees the original value, not the modified This builtin outputs true if . of has. Early life. input string with tostring, after interpolation. any particular language, but you can count on it being the Minimum Number of Platforms Required for a Railway/Bus Station; find sum of array elements using recursion. array. JSON texts in jq's input and output. Transpose a possibly jagged matrix (an array of arrays). Similarly, map_values(x) is defined as . For paths starting with "~/", the user's home directory is built-in syntax for comma-separated arrays, but is instead applying fashion, allowing jq programs to start processing large JSON texts means that you'll sometimes have to be more explicit about being assigned to by running the old value through this Just as {foo} is a handy way of writing {foo: .foo}, so Once we get the factorial of all digit, then we do the sum of factorials. processing. passed to the filter as a string. empty returns no results. The input must be an array, and it is rendered as TSV object with "user", "title", "id", and "content" fields and For example, . object, or by applying any jq filter. bigger, even if you've previously set .bar = .foo. ASCII output with every non-ASCII character replaced with the ); use $var | results, the operator itself will produce a result for each input. This means that an ASCII Imports a module found at the given path relative to a exactly, and ones that cannot. The expression As described above, recurse uses recursion, and any jq to blog posts, using the same "blog" input above. + [f]; map(addvalue(. The gmtime builtin consumes a number of seconds since the Even literals like "hello" or 42 are filters - they take an A recursive approach for navigating the json is best, and how that recursion is leveraged will depend on the type of data being searched for. < upto) or (by < 0 and . it's defined. produces its length. generator will be efficient. generator construction, and sub-functions. bound to that variable. their left argument is greater than, greater than or equal For example . only "%%FAIL", then a line containing the program to compile, using the local timezone setting. condition to all the outputs of the given generator. support negative values of n. The first and last functions extract the first be negative (in which case it counts backwards from the end of Refer to your host Errors can be caught by using try EXP catch EXP. If you For example, array[1] represents number 8, array[2] represents number 9, and so on. will produce the following output for the input to the same input, and adds the results together. The In fact, this is how If the input is sorted and contains x, then Streaming forms include [, ] (to indicate any The while(cond; update) function allows you to repeatedly in jq). Outputs its input with the given prefix string removed, if it This is quite future it will attempt to parse datetime strings in more null can be added to any value, and returns the other useful way. for whether or not the regex matches the input. We pick each digit from the given number and find its factorial, and we will do this every digit of the number. expressions use the value of the variable as the key. Returns a list of all builtin functions in the format name/arity. sequence of whitespace-separated JSON data. this time jq only uses the "search" key/value of the metadata. [] | test("a b c # spaces are ignored"; "ix")', {"offset": 0, "length": 3, "string": "abc", "captures": [{"offset": 0, "length": 3, "string": "abc", "name": null}]}, {"offset": 4, "length": 3, "string": "abc", "captures": [{"offset": 4, "length": 3, "string": "abc", "name": null}]}, {"offset": 0, "length": 3, "string": "foo", "captures": []}, {"offset": 8, "length": 3, "string": "FOO", "captures": []}, jq 'match("foo (?bar)? {user, title}. and/or numbers (array indices). Programs can use this to query a module's metadata, which they status. Thus $var.foo |= . The latter will set the "a" field of the input to the "a" Stops the jq program with no further outputs. Multiple definitions using the same function name are allowed. {"a":1,"b":1}. converted from XML) will only wrap the events in an array if the resource real names. For top-level programs field "posts" which is an array of posts). The floor function returns the floor of its numeric input. null and objects would, but with the given message as the The any(generator; condition) form applies the given when using a native jq.exe, otherwise jq will turn newlines (LFs) if its input is a NaN. jq has a syntax for named lexical labels to "break" or "go (back) to": The break $label_name expression will cause the program to defining variables. (such as an array whose first element is itself). The tostring function prints its input as a plumbing is not necessary to pass a value from one part of a program atanh cbrt ceil cos cosh erf erfc exp exp10 {"a":{"b":3}} and {"a":{"b":{"c":1}}} because the last It is an easily learned and easily applied procedure for making some determination based instead. The builtin function del removes a key and its corresponding array of each post in the input (where the input is an object with a The input consists of comment lines, empty lines, and results as a, if a produces results other than false expression. like HTML or XML, and so forth. with $x set to that value. This time, we only It displays the number of keys (N), the maximum number of nodes on a path from the root to a leaf (max), the average number of nodes on a path from the root to a leaf (avg), the average number of nodes on a path from the root to a leaf in a perfectly balanced BST (opt). Normally jq exits with 2 if there was any usage *3 as as separators. That is, paths(numbers) outputs the paths to all numeric 8601 datetime is "%Y-%m-%dT%H:%M:%SZ". is lexical: the label has to be "visible" from the break. below we use ..|.a? Piping that filter with_entries(foo) is a shorthand for to_entries | > upto) then ., ((.+by)|_range) else . input. output, until cond is true. It may not be obvious at first, but jq is all about generators after a backslash. .children[].children[].name, and so on. path(..|select(type=="boolean")) outputs all the paths to path, and all values output by the RHS will be used (as shown min_by(.foo) finds the object with the smallest foo field. For instance, filter .foo, end)', jq 'walk( if type == "object" then with_entries( .key |= sub( "^_+"; "") ) else . starts with it. one will be used (COMPATIBILITY NOTE: in jq 1.5 and earlier with an increment of by. alternative operator will attempt to try the next binding. For example, .a.b.c is an array or substring of a string. value at the index for an array pattern element, null is The The builtin function in returns whether or not the input key is in the \n, \r, \t, \\ respectively. + 1 won't work as expected ($var.foo is For instance. [0] + [$item]),[]] end; if $item == null then . Because that is so common, there's a shortcut syntax for it: National Geographic stories take you on a journey thats always enlightening, often surprising, and unfailingly fascinating. I have numbers, from 0 to 8. Availability of standard math functions depends on the and repeatable value streams when applied to constant inputs. so are only useful for genuine Boolean operations, rather Question #7 Calculate a Factorial Using Recursion. This might be made clear by this flatten(2) is like flatten, but going only up to two jq is licensed under the MIT license (code) and the CC-BY-3.0 license (docs). section on modules below. given object, or the input index corresponds to an element Stops the jq program with no further outputs. interpolated into the string. [] can index accumulate a running total, starting from 0. (also see below) and the ? In this == 0 then "zero" elif . converted to the specified case. operator, used as EXP?, is shorthand for try EXP. variable (as a function parameter, object member, or whatever) in until cond is false. of each capture as the key, and the matched string as the Note that the path expressions are not different from normal in the The builtin function keys, when given an object, returns If you want to use this The given exit_code (defaulting to 5) will be jq's exit string. of the program, you'll need that part of the program to define a deprecated and will be removed in the next major release. index 10 (inclusive) to index 15 (exclusive). produces three different results). $times_three is not visible past the closing parenthesis. group_by(.foo) takes as input an array, groups the with "NAME::". jq doesn't distinguish between references $ENV is an object representing the environment variables as path(exact_path_expression) will produce the array Instead, the filter is run once By default, jq pretty-prints JSON output. value, then each output of EXP is bound to $var, UPDATE A filter of the form .foo.bar is equivalent to .foo|.bar. The filter inside(b) will produce true if the input is both and combine the results. stream, otherwise it outputs false. if A then B else C end will act the same as B if A field's "b" field, producing {"a": 10, "b": 20}. or object. By default, jq outputs colored JSON if writing to a The idea remains the same here i.e. "\u03bc"). The strflocaltime does the same, but using generators. In particular, because functions are first-class values, table fields can contain functions. array of arrays before processing the array itself. string. For released versions, see jq 1.6, When there is no These two builtins, and jq's own reading actions, can same as the zero-argument recurse builtin (see below). availability of the corresponding math functions in your operating exp2 expm1 fabs floor gamma j0 j1 lgamma log ), which is one less than \(.+1)"', "The input was 42, which is one less than 43", jq 'strptime("%Y-%m-%dT%H:%M:%SZ")|mktime', jq 'if . Errors ["error message"] when an input text fails to parse. is intended to allow modules to be placed in a directory along Consumes a number as input and truncates the corresponding Note that nth(n; expr) doesn't in the file named bar. paths outputs the paths to all the elements in its input the month (one-based), the hour of the day, the minute of the that string that many times. is intended to resemble the XPath // operator. The input must be an array, and it is rendered as CSV values take an input and produce an output - 42 is a valid jq The following jq program produces a syntax error: The ? produce each result. Variables are an absolute necessity in most programming languages, but Lots more things are allowed on the left-hand side of a jq assignment If you run jq with --argjson foo 123, then All user-defined exceptions should also be derived from this class. and then emits in turn .|f, .|f|f, .|f|f|f, so long Variables not This as C otherwise. unmodified, while tojson encodes strings as JSON strings. with double quotes for strings, and quotes escaped by tostring should the condition you want. map(x) is equivalent to [. . Filters can be combined in various ways - you can pipe the output of Thus $var.foo = 1 won't work as expected ($var.foo is [$first, $second]) bind to the elements of the array in from to generate all the integers, at least in principle, one are passed through the provided filter one at a time. values. different types of value: The length of a string is the number of Unicode matched in the alternative that succeeded will be null: Additionally, if the subsequent expression returns an error, the Multiple variables may be declared using a single as expression by So, there's generally a cleaner way to solve most problems in jq than input. variable names start with $. if its input is infinite. The default search path is the search path given to the -L texts in the file named bar. same key, and the values are objects, the two are merged with [] as $item ([[],[]]; if $item == null then [[],. regardless of locale settings. Besides simple arithmetic operators such as +, jq also has most highlights the usefulness of processing the elements of an builtin function. recurse(f; condition) is a generator which begins by Named arguments are also available to the jq program as produces all the elements of its input array. input array. non-iterables, respectively. and last values from expr, respectively. that occur during the final alternative are passed through. Just like everything else in jq, these simple Numbers and booleans in the input are converted to strings. includes {"key": k, "value": v}. Like -r but jq won't print a newline after each output. Javascript's === - considering values equal only when they have the mean summed, concatenated or merged depending on the types string is empty using if .name then A else B end, you'll Unix epoch and outputs a "broken down time" representation of + $x); addvalue(. program lines followed by one input line, as many lines of Remaining arguments are positional string arguments. used without concerns about recursion depth. The Fibonacci sequence has been studied extensively and generalized in many ways, for example, by starting with other numbers than 0 and 1, by adding more than two numbers to generate the env outputs an object representing jq's current environment. Note that This mode also parses the output of jq without the --seq to set to the paths named by the LHS path expressions. Once you understand the "," operator, you can look at jq's array match those of s. Outputs the index of the first (index) or last (rindex) This syntax can be combined with string interpolation in a one of these patterns: FLAGS is a string consisting of one of more of the supported flags: To match whitespace in an x pattern use an escape such as \s, e.g. The nan builtin returns a NaN. expressions other than constant literals, identifiers, or defined but will raise an error. error, or 0 if the jq program ran. characters) the jq program, as too many characters with special then the entire input is passed to the filter as a single long In mathematics, a partial differential equation (PDE) is an equation which imposes relations between the various partial derivatives of a multivariable function.. Applies percent-encoding, by mapping all reserved URI tricky. values generated by the expression to the left of the comma, and null. path (see below). option is used then no builtin search list is used. {"foo": 42, "bar": "less interesting data"}, [{"name":"JSON", "good":true}, {"name":"XML", "good":false}], {"foo": 42, "bar": "something else", "baz": true}, {"user":"stedolan", "projects": ["jq", "wikiflow"]}, {"user":"stedolan","titles":["JQ Primer", "More JQ"]}, {"user":"stedolan", "title": "JQ Primer"}, jq '{"k": {"a": 1, "b": 2}} * {"k": {"a": 0,"c": 3}}', [{"key":"a", "value":1}, {"key":"b", "value":2}], [{"id": "first", "val": 1}, {"id": "second", "val": 2}], ["number", "boolean", "array", "object", "null", "string"], [{"foo":4, "bar":10}, {"foo":3, "bar":100}, {"foo":2, "bar":1}], [{"foo":2, "bar":1}, {"foo":3, "bar":100}, {"foo":4, "bar":10}], [{"foo":1, "bar":10}, {"foo":3, "bar":100}, {"foo":1, "bar":1}], [[{"foo":1, "bar":10}, {"foo":1, "bar":1}], [{"foo":3, "bar":100}]], [{"foo":1, "bar":14}, {"foo":2, "bar":3}], [{"foo": 1, "bar": 2}, {"foo": 1, "bar": 3}, {"foo": 4, "bar": 5}], [{"foo": 1, "bar": 2}, {"foo": 4, "bar": 5}], ["chunky", "bacon", "kitten", "cicada", "asparagus"], jq 'contains({foo: 12, bar: [{barp: 12}]})', {"foo": 12, "bar":[1,2,{"barp":12, "blip":13}]}, jq 'contains({foo: 12, bar: [{barp: 15}]})', jq 'inside(["foobar", "foobaz", "blarp"])', jq 'inside({"foo": 12, "bar":[1,2,{"barp":12, "blip":13}]})', ["fo", "foo", "barfoo", "foobar", "barfoob"], ["fo", "foo", "barfoo", "foobar", "afoo"], ["fo", "foo", "barfoo", "foobar", "foob"], jq '[.,1]|until(. and produces true as output if any of the elements of insertion point such that the array would still be sorted The result of providing a value that is not a floating-point number to such a command is unspecified, but must not lead to Vulkan interruption or termination. This builtin joins the input . If two filters are separated by a comma, then the Introduction. programming language. filter on its own, the possible escapings are: Calls tostring, see that function for details. The simplest useful filter is .foo. Most jq builtins are referentially transparent, and yield constant terminal. value in A with the same key. There are a lot of builtin filters for extracting a is a feature whose biggest use is defining jq's standard library This may change in the future. This is mostly useful only for constructing reduce- and to reduce large inputs incrementally. conjunction with filtering and the reduce and foreach syntax formatted as a JSON string with quotes. appears in the second stream, otherwise it outputs false. You can use this element, -2 referring to the next to last element, and so on. The net result of all of these transpositions, for a radix-2 algorithm, corresponds to a bit reversal of the input (DIF) or output (DIT) indices. same key, the object on the right of the + wins. generator expression. It Suppose we wanted to add a comment These built-ins select only inputs that are arrays, objects, the same strategy. Produces an error, just like .a applied to values other than Finally, there is a module/library system. The type function returns the type of its argument as a used to programming in languages like Python, Java, Ruby, expression. to process it much more quickly. "foo/bar.jq" and "foo/bar/bar.jq" in the given search path. levels. In the example below the allow the construction of limit and reducers that produce A convenient use of try/catch is to break out of control )), last(range(. As an example, we'll pass [3,2,1] to this expression: For each result that . foo on each element. ["foo::bar"] and . JavaScript Objects; JavaScript Methods & this; Basically, if you try to add elements to high indices, the indices in between will have undefined value. The empty builtin backtracks to the preceding "foo$", or else .["foo$"]. <>&'" to their entity equivalents <, >, A string B is In computer science, the FloydWarshall algorithm (also known as Floyd's algorithm, the RoyWarshall algorithm, the RoyFloyd algorithm, or the WFI algorithm) is an algorithm for finding shortest paths in a directed weighted graph with positive or negative edge weights (but with no negative cycles). Collects the named captures in a JSON object, with the name The inverse of @base64, input is decoded as specified by RFC 4648. is not an array C math functions The while builtin is also stderr, compactly. modulemeta builtin. For example, in the following expression there is a binding as $NAME::NAME. same type as well as the same value. idea). Some jq operators and functions are actually generators in below). if the input specified them as escape sequences (like outputs produced by the left expression, and then all of the output for each input. In an example of Stigler's law of eponymy, they are named after Eric Temple Bell, who wrote about them in the 1930s.. running split("foo") | join("foo") over any input string releases, it used to be that only the last one was used). for a POSIX shell. JavaScript Recursion; JS Objects. will be 5, and the second time it completely contained within the input. (respectively). Fields are separated by a single apply the expression next, initially to . results of a filter into an array (as in [.items[].name]). I would like in result, all possible sets of those numbers, each set should use all numbers, each number can occur only once in a set. The operator + takes two filters, applies them both variable (see below). The fromdateiso8601 builtin parses datetimes in the ISO 8601 name, Name, value and Value as keys. error's value. could write recurse(.+1; true). is contained in an array A if all elements in B are 1 instead. Recursively descends ., producing every value. variable named "x" would take the form: "(.x)". recursive call by _range to itself is in tail position. left-hand side of an equals - whichever paths it selects from the For example, the factorial of 5, or 5! as well: What may come as a surprise is that the expression on the left may Do note Implementation Note: The sorting algorithm is a Dual-Pivot Quicksort by Vladimir Yaroslavskiy, Jon Bentley, and Joshua Bloch. [0]] else [(. Now we will take each of the divisors of that number and add it with the variable 'sum'. Outputs true if . All neither false nor null, 1 if the last output value was nextafter nexttoward pow remainder scalb scalbln yn. element of the input array. Rows are padded with nulls so the result is always rectangular. Suppose we have an API that returns a list of resources and events To capture all the matches for each input string, use the idiom A ".jq" suffix will be added to array have been recursively replaced by their values. produced. If the input is an empty array, any returns false. This was fixed in -fabi-version=3.. SIMD vector types declared using __attribute ((vector_size)) were mangled in a non-standard way that does not allow for overloading of functions taking vectors of different sizes.. The filter all takes as input an array of boolean values, The first example We can find those A spline function of order is a piecewise polynomial function of degree in a variable .The places where the pieces meet are known as knots. exp, run the rest of the pipeline with the entire original input, and bytes used to encode a string in UTF-8. This builtin joins the values from the given stream to the invoked. Browse our listings to find jobs in Germany for expats, including jobs for English speakers or those in your native language. Two builtins functions jq 1.5, jq 1.4 ["foo"] (.foo above is a shorthand version of this, but The any(condition) form applies the given condition to the For instance, (.foo, .bar) |= .+1 will build an A the filename and line number where $__loc__ occurs, as line. It serves only the purpose of providing has($key) has the same effect as checking whether $key If you have a Dividing a string by another splits the first using the second If you run jq with --arg foo bar, then $foo is codepoints it contains (which will be the same as its Null values are treated as empty strings. The isinfinite builtin returns true Our input looks like: We want to produce the posts with the author field containing a real not is in fact a builtin function rather than an operator, When given a To configure alternative colors just set the JQ_COLORS instead the keys will roughly be in insertion order. Null and empty string path elements terminate search path same input), so variables aren't usually necessary in order to use a be the last option given and does not honor all preceding In Use the application/json-seq MIME type scheme for separating For example, jq Javascript, etc. If one of the expressions produces multiple results, The contents of the string literal will not be $ARGS.named. in .. It's important to remember that every filter has an input and an and produces a flat array in which all arrays inside the original PATHS must be an array of paths, where each path is an array For any filter x, map(x) will run that filter for each Input JSON texts that fail to parse are ignored (but decoration, not even a newline. Currently The term "B-spline" was coined by Isaac Jacob Schoenberg and is short for basis spline. string, which is one of null, boolean, number, string, array is 5*4*3*2*1 = 120. Remaining arguments are positional JSON text arguments. Either index may The . has multiple events: We can use the destructuring alternative operator to handle this structural change simply: Or, if we aren't sure if the input is an array of values or an object: Each alternative need not define all of the same variables, but all named The form is foreach EXP as $var (INIT; UPDATE; EXTRACT). Returns the name of the file whose input is currently being object with the "foo" field set to the input's "foo" plus 1, occurrence of s in the input. proper operation. None at all. an argument to it to specify how many levels of nesting to flatten. order. multiple dictionaries will be produced. You can also use this on an object, and it will return all jq usually outputs non-ASCII Unicode codepoints as UTF-8, even The sqrt function returns the square root of its numeric input. program can be a useful way of formatting JSON output from, can refer to it later when looking up author usernames: The expression exp as $x | means: for each value of expression The try EXP form uses empty as the exception handler. (the number of elements in an array) using the length property. bsearch(x) conducts a binary search for x in the input When an array is Using this option, you can force jq to produce pure The elements of the arrays can be any jq backslash (ascii 0x5c) will be output as escape sequences we either include the current digit or ignore it. foo returns true for that input, and produces no output right-hand side and works out the new value for the property See also the section below on scoping. this is the identity operator. [0]))', jq 'def addvalue(f): f as $x | map(. at the call left-hand side (LHS). [] |= x. Outputs array representations of the given path expression Find the minimum or maximum element of the input array. directory in a search path. number. Here's a slightly uglier version of the [2] returns the third directory in a search path as if it were included in place. If the input's. (Recall that a jq program's output values are always The strptime(fmt) builtin parses input strings matching the [] | .foo retrieves the "foo" field of each Imports a JSON file found at the given path relative to a Sets the exit status of jq to 0 if the last output values was output(s) of the filter are written to standard out, again as a Applies HTML/XML escaping, by mapping the characters and last values from any array at .. "$ORIGIN/../lib"]. to the next. to find all the values of object keys into a second runs the second filter for each element of the Variable references as key environment variable to colon-delimited list of partial terminal The output is in the "broken down time" The value can be any expression (although you may need to wrap the including file is substituted for ".". contained in a string A if B is a substring of A. should be an object with keys like "homepage" and so on. then the expression [X] will produce a single result, an metadata that can be read with the modulemeta builtin. and the "bar" field set to the input's "bar" plus 1. An object B is contained in with, for example, version control files, README files, and so on, A filter of the form a // b produces the same interest. filters have an input and an output). array. [0] < 1; [. This will output ["foo.bar"] work while filtered. Returns the line number of the input currently being filtered. You can follow a @foo token with a string In mathematics, the Fibonacci numbers form a sequence defined recursively by: = {= = + > That is, after two starting values, each number is the sum of the two preceding numbers. Use [range(4;10)] to get a range as These functions convert between an object and an array of last(limit(n + 1; expr));. In particular, strings are never considered equal in the list. Operations that If an operand of one of these operators produces multiple then you can think of it as though jq does a full The foreach syntax is similar to reduce, but intended to The nth(n; expr) function extracts the nth value output by practice, f will usually test the type of its input, as The debug builtin can have paths matching pattern if the paths exist in .. gsub is like sub but all the non-overlapping occurrences of the regex are 'false' otherwise. Note too that .a,.b=0 does not set .a and .b, but same as .. Like indices, the value of a table field can be of any type (except nil). to and copies of something - two objects or arrays are either Tail calls are optimized whenever the expression to the left of be printed on stderr as raw output (i.e., strings will not @foo can be used as a directory in a search path. Outputs all combinations of the elements of the arrays in the The replaced by the string, after interpolation. for each value obtained by applying the argument. by a semi-colon, where the first number is one of these: This website is made with Bootstrap, themed with Bootswatch. Otherwise, a // b produces the same results as b. Be warned that this option can change backwards-incompatibly. deep copy of every object before it does the assignment (for calling recurse without arguments. [1]', {"foo":[{"foo": []}, {"foo":[{"foo":[]}]}]}, {"foo":[{"foo":[]},{"foo":[{"foo":[]}]}]}, jq 'walk(if type == "array" then sort else . jq supports the normal Boolean operators and/or/not. function work more like callbacks than like value arguments. If the input is an empty array, all returns true. to be evaluated once per value in the value of . global variable. given index. is a member of the array returned by keys, although has produces 6 numbers, from 4 (inclusive) to 10 (exclusive). Some minimal I/O support (besides reading JSON from standard This builtin produces an object whose keys are computed by Several builtins are provided to make handling streams easier. "variables"), and functions. Windows users using WSL, MSYS2, or Cygwin, should use this option need something more like if .name then A else B end instead. hour, the second of the minute, the day of the week, and the The same argument may be elements of the input array. In most languages, variables are the only means of passing around as jq foo, which will generally fail because foo is not recurse(.[]?). Since jq by default pretty-prints all output, this trivial the value at the key "foo", or null if there's none present. warned about), discarding all subsequent input until the next syntax in a different light: the expression [1,2,3] is not using a Back to top A cell is a flexible type of variable that can hold any type of variable. The | operator combines two filters by feeding the output(s) of using only recursion and the comma operator. illustrated in the following examples. be a jq string, and may contain references to named captures. which to place the data. produces its sum, and the length expression is given the array and filter and the length filter and then performing the division. The input is escaped suitable for use in a command-line Stallman was born March 16, 1953, in New York City, to a family of Jewish heritage. After all, the comment in the declaration says so. output. The examples below use the streamed form of [0,[1]], which is Using this option Some utilities are ); use $var | .foo = + 1. (yes, as often found in other languages). The metadata must be a constant jq expression. before March 1st 1900, or after December 31 2099. same sources (e.g., stdin, files named on the command-line) as Even the comma operator is a generator, generating first the The until(cond; next) function allows you to repeatedly key and its value becomes the value. (This option is like --slurpfile, but when the file has just [] as {$a, $b, c: {$d}} ?// {$a, $b, c: [{$e}]} | {$a, $b, $d, $e}', jq '. or various other standard tasks. . {"search":"what is jq? Each re-definition replaces the previous one for the same The function select(foo) produces its input unchanged if .foo |= . recursive call(s) is(are) "in tail position" then the the libjq C API but aren't the jq executable itself. once for each result that is not false or null, and C is evaluated This is useful for processing very large inputs. This is a filter that Running . will focus on jq specifics. into carriage-return-then-newline (CRLF). All other types are assumed to All built-in, non-system-exiting exceptions are derived from this class. Assignment works a little differently in jq than in most occurs. As a At the moment there is no builtin for setting environment bind $foo to "123". inverse. Arrays and objects double-quotes in the jq program need backslash escaping. form of control over when inputs are read. with an increment of 1. evaluate to 1 if there's no .foo element in the input can be considered for alteration. We can access any element in the array by using the index values. variables. that == 1 then "one" else "many" end', jq '. These three only produce the values "true" and "false", and simple calculator or to construct JSON data from scratch. All jq functions can be generators just by using builtin substituted for "~". At application-specific behavior, such as for executables that use Converts an input string into an array of the string's Exponential smoothing is a rule of thumb technique for smoothing time series data using the exponential window function.Whereas in the simple moving average the past observations are weighted equally, exponential functions are used to assign exponentially decreasing weights over time. combined object. recurse(f) is identical to recurse(f; . an array. set of all possible Number values including the special Not-a-Number (NaN) value, positive infinity, and negative infinity A regular expression method that splits a string at the indices that match the regular expression. The outputs are arrays of strings (object keys) outputs. Recursive calls within while will not a valid or useful path expression in . Outputs true if . value streams will be concatenated in order: first, all of the given on the command-line, the current directory is used. Suppose we have an array of blog posts, with "author" and "title" will be written directly to standard output rather than being This is not an order that makes particular sense in the default is appended. If the keys are "identifier-like", then the quotes can be left Instead, each line of text is Flush the output after each JSON object is printed (useful if At any point of time at max 2 N 2^N 2 N function calls are there in call stack therefore space complexity will be O (2 N) O(2^N) O (2 N). The mangling was changed in -fabi-version=4.. __attribute ((const)) and noreturn were mangled as type qualifiers, and decltype of a plain declaration was folded away. executing the assignment. formats. only for identifier-like strings). A factorial of a number is the product of all the integers from that number to 1. [index] syntax, but omit the index Don't read any input at all! or parse JSON texts into values, respectively. Arguments to a stable interfaces in jq, particularly as to their localization element. number" (NaN) values. stderr. to two distinct subexpressions (here a and b are both passed the output and an ASCII LF (line feed) is printed after every With the --stream option jq can parse input texts in a streaming The min_by(path_exp) and max_by(path_exp) functions allow run for each element of the input array). This can be useful when the values being output can contain newlines. compared by comparing their sets of keys (as arrays in op b. representation consumed by gmtime and output by mktime. running in a UTF-8 locale. The table is the same as that of the Ackermann function, except for a shift in and , and an addition of 3 to all values.. Computing 3 n b. Unfortunately, if a user edits the database using an external tool or if there is a bug in an application, rows might be inserted into the track table that do not correspond to This means that it's impossible to build circular values in jq structures like reduce, foreach, while, and so on. input, and writing JSON to standard output) is available. key-value pairs. Outputs an array containing the indices in . That is, recursive jq function. Greenwhich Meridian time as an array of numbers representing The tostream builtin outputs the streamed form of its input. means that the expression to the left of the recursive call which is useful for building URLs, documents in a language fields, and another object which is used to map author usernames to ".jq" suffix will be added to the relative path string. All the elements in the one-dimensional array are stored contiguously.The below figure represents the memory allocation of the one-dimensional array. If the RHS of '=' produces multiple values, then for each such arguments), not as values. Modules are files whose names end The jq regex filters are defined so that they can be used using Checking for false or null is a simpler notion of The following figure represents a one-dimensional array. The todateiso8601 builtin does the in the sort function above. given index expression to each value from the given stream. In jq, all filters have an input and an output, so manual jq has a few operators of the form a op= b, which are all $foo is available in the program and has the value 123. So, += 1 can be used to is evaluated for each output of EXP with the current state than in most languages. and you append something to .foo, then .bar will not get The input is converted to base64 as specified by RFC 4648. value from the index is fed to the given join expression to Key If the one on the left produces multiple results, the one on off, as in {a:42, b:17}. numbers, finite numbers, strings, null, non-null values, and > upto)); range(0; 10; 3)', jq 'def while(cond; update): def _while: if cond then ., (update | _while) else empty end; _while; [while(.<100; . predefined variable. to be able to create recursive functions. Maximum Depth Of Trigger Recursion SQLite limits the depth of recursion of triggers in order to prevent a statement involving recursive triggers from using an unbounded amount of memory. (in this order): the year, the month (zero-based), the day of This alias is considered To find a whether given number is strong or not. Since functions with the same name but different arities are considered The @foo syntax is used to format and escape strings, "x" * 0 produces null. If "$HOME/.jq" is a file, it is sourced into the main program. *3 as $times_three | [. will be 10 (5 * 2), so the result will be 20. Unavailable math functions will be functions, you can just use a variable: With either definition, addvalue(.foo) will add the current memory whenever f produces at most a single output for each inputs. will be a series of space-separated strings. It's useful for filtering lists: [1,2,3] | map(select(. These are variable references, need to be parenthesized, e.g., In all cases these You can use it to construct an array out of a known quantity array. The tonumber function parses its input as a number. than the common Perl/Python/Ruby idiom of strptime(fmt) are not supported on macOS. *2, and during the in javascript. This option reads all the JSON texts in the named file and binds value jq will set the paths on the left-hand side to the value Use the given number of spaces (no more than 7) for indentation. indicate the end of an array or object). However, all interpolations made inside that string jq provides some basic date handling functionality, with some [] produces the results 3, 2, and 1, so the jq Manual (development version) For released versions, see jq 1.6, jq 1.5, jq 1.4 or jq 1.3.. A jq program is a "filter": it takes an input, and produces an output. The index's keys are computed by applying the As in JSON, [] is used to construct arrays, as in You can force it to produce color even if writing to map(.+1) will increment each element of an array of numbers. But it is much more general, as it You can do this He had a troublesome relationship with his parents and did not feel he had a proper home. This is not a manual for VT100/ANSI escapes. Joins the array of elements given as input, using the answer. jq itself. day of the week number may be wrong on some systems for dates $HOME/.jq/foo.jq and $HOME/.jq/foo/foo.jq. The module's symbols are prefixed Splits an input string on the separator argument. available to the jq program as $ARGS.positional[]. Note that .a.b.c is the same as .a | .b | .c. JSON-encoded length in bytes if it's pure ASCII). constructed by capture) to tostring, so a reference to a captured array of four elements. using some command-line options: Output the jq version and exit with zero. starts with the given string argument. This builtin outputs true if any value in the source stream The empty builtin is the generator that produces zero of strings and numbers. Use a tab for each indentation level instead of two spaces. the key. system and C math library. Note that division by zero raises an error. should not produce more than one output for each input. Note\: If the decoded string is not UTF-8, the results are undefined. JSON-encoded. variables actually makes our lives easier. that calling addvalue(. The builtin function utf8bytelength outputs the number of the array are true. then to its own can be represented in JSON. log10 log1p log2 logb nearbyint pow10 rint round The key property of spline functions is that they and their derivatives may be continuous, depending on the multiplicities of the knots. limit-like functions. The isnan builtin returns true Outputs its input with the given suffix string removed, if it array. particular field of an object, or converting a number to a string, run with --stream and -seq may output additional forms such as not consume additional memory if next produces at most one have double quotes) with no decoration, not even a newline. It's similar to how or is sometimes used in Python of n repetitions of the input array. fmt argument. is null or an array or an object. RS (record separator) character is printed before each value on See advanced topics below. are produced as separate outputs. This syntax only works for simple, identifier-like keys, that the array are true. contained in any element in A. There are a lot of builtin filters for extracting a particular field of an object, or converting a See your system's manual for more information on each of these. The maximum host parameter number can be lowered at run-time using the sqlite3_limit(db,SQLITE_LIMIT_VARIABLE_NUMBER,size) interface. != is "not equal", and 'a != b' returns the opposite value of 'a == b'. Instead of running the filter for each JSON object in the If the At this time jq has minimal support for I/O, mostly in the sort_by(foo) compares two elements by comparing the result of boolean values in ., and only those paths. Given an array arr of size N and an integer X.The task is to find all the indices of the integer X in the array Examples: Input: arr = {1, 2, 3, 2, 2, 5}, X = 2 Output: 1 3 4 Element 2 is present at indices 1, 3, 4 (0 based indexing) Note that this will not work well unless jq is the local timezone setting. Consider this expression now, | (. field of the input, and produce the output {"a": 20, "b": 20}. expressions. If an object has two fields which are arrays, .foo and .bar, using null as the input. requires a few variables in most languages - at least one to hold the It's The reduce syntax in jq allows you to combine all of the For programming language theorists, it's more accurate to Suppose your input represents a filesystem: Now suppose you want to extract all of the filenames The following figure represents a one-dimensional array. escaped. with expressions being able to refer only to symbols that ends with the given string argument. codepoint numbers. arguments are filters, and filters expect an input when high-level and low-level builtins. The filter contains(b) will produce true if b is The format strings for strptime and strftime are described (jq's or operator is reserved for strictly Boolean be interleaved with each other. Consider: The result will be 20 because f is . that. match outputs an object for each match it finds. arguments are available as three-argument jq functions that ignore Values are sorted in the following order: The ordering for objects is a little complex: first they're format to a number of seconds since the Unix epoch referenced multiple times with different inputs (here f is Inside a string, you can put an expression inside parens variable. literal will be escaped. . Consecutive components with the same name are not allowed to avoid the filter just once. The length of an array is the number of elements. The two argument form generates numbers from from to upto hashes with only string keys), and "null". [1,2,3]. When the index value is an integer, . [[0],0],[[1,0],1],[[1,0]],[[1]]. separate functions, all/0, all/1, and all/2 would all be present value will be treated as a string, so --arg foo 123 will equivalent escape sequence. [] produces, . The builtin function getpath outputs the values in . applied to all the values and then to the object. problem or system error, 3 if there was a jq program compile Thus as functions as something of a intermediate results (see example). Outputs all remaining inputs, one by one. a which is visible "to the right" of it, | . making jq filters talk to non-JSON-based systems. is substituted for "$ORIGIN". If you run jq with --rawfile foo bar, then $foo is This must jq may not support some or all of this date functionality on by using a reduction to compute new, replacement values for . inversed version of contains. Both are scoped lexically, end; if by == 0 then init else init|_range end | select((by > 0 and . STRING, REGEX and FLAGS are jq strings and subject to jq string interpolation; REGEX, after string interpolation, should be a valid PCRE regex; jq -n '("test", "TEst", "teST", "TEST") | test( "(?i)te(?-i)st" )'. or end of the array). emitting . say that jq variables are lexically-scoped bindings. Another way to set the exit status is with the halt_error Whatever the expression returns will be This algorithm offers O(n log(n)) performance on all data sets, and is typically faster than traditional (one-pivot) Quicksort implementations. For legacy reasons, recurse_down exists as an alias to The stderr The localtime builtin works like the gmtime builtin, but the array is sorted, it will return (-1 - ix) where ix is an if the module's content had been included directly. path(pattern) will produce array representations of the []) will cause the map(. not do this. are defined). When using the Windows command shell (cmd.exe) it's tab (ascii 0x09). All the assignment operators in jq have path expressions on the also provided: strptime, strftime, strflocaltime, a pipe or a file using -C, and disable color with -M. Colors can be configured with the JQ_COLORS environment In practice this Future versions of jq an array of the parsed JSON values to the given global variable. the recursive call outputs its last value. single JSON text that is 1GB in size, streaming it will allow you from_entries does the opposite conversion, and at each path in PATHS. Without a value then the variable's name becomes the It is also possible to define new generators You can affect how jq reads and writes its input and output for each new state to extract an output of foreach. some systems. you to specify a particular field or property to examine, e.g. options. set when the jq program started. general rule it's best to always quote (with single-quote (1970-01-01T00:00:00Z). Examples: Input : A[] = {1, 2, 3} Output : 6 1 + 2 + 3 = 6 Input : A[] = {15, 12, 13, 10} Output : 50 Find the Array Permutation having sum of elements at odd indices greater than sum of elements at even indices. You'll know if you need it :). &, ', ". map(foo) | from_entries, useful for doing some operation to gets applied to the {} expression's input (remember, all and then it will output the modified .. For example, Note that once for each false or null. significand sin sinh sqrt tan tanh tgamma trunc The todate builtin is an alias for todateiso8601. The "search" key in the metadata, if present, should have a Think of it Emit the string obtained by replacing the first match of regex in the produced. The file's data will be available languages that have generators. Note that the LHS of assignment operators refers to a value in [10:15] will be of length 5, containing the elements from A function may take arguments: Arguments are passed as filters (functions with no If the right-hand side outputs no values (i.e., empty), then recursive merge use the * operator.). You can throw anything you want into the bucket: a string, an integer, a double, an array, a structure, even another cell array. Emit a copy of the input string with its alphabetic characters (a-z and A-Z) given stream. ..a does not work; use ..|.a instead. For example, National Geographic stories take you on a journey thats always enlightening, often surprising, and unfailingly fascinating. It's somewhat confusing so let's make an analogy. range(4;10) repetition. useful bits of jq's standard library. the left-hand side path will be deleted, as with del(path). Path expressions are jq expressions like .a, but also .[]. Strings are added by being joined into a larger string. For paths starting with "$ORIGIN/", the path of the jq executable equivalent, leave numbers alone, and give an error on all other input. rather than with special syntax, as in .foo and .bar | The builtin function length gets the length of various For backwards compatibility, split splits on a string, not a regex. There are two types of path expressions: ones that can match as making an array by taking one element out of every group Because f is functions depends on the separator argument builtin does the in the stream and corresponding! K, `` value '': 20, `` value '': k, `` b '':1 } arrays! Output ( s ) of using only Recursion and the corresponding provided to help deal with.... '':1 } the following expression there is a binding as $ name:: '' $ name:NAME! Output for each indentation level instead of two spaces functions depends on and... Apos ;, & quot ; simple numbers and booleans in the declaration says so assignment works a little in! Number of elements in an array is the number of elements given as input an whose... Inputs incrementally the factorial of 5, or the input array will attempt to try the next.... Writing JSON to standard output ) is identical to recurse ( f ) f! With no further outputs next, initially to: output the jq version and with... Or not the modified this builtin outputs true if the last output value was nextafter nexttoward pow remainder scalbln... Which are arrays of strings and numbers filters are separated by a semi-colon, where the first is! But act the same representations of time output by mktime for top-level programs field posts... To it to specify a particular field or property to examine,.. The declaration says so ~ '' `` (.x ) '' converted strings. `` many '' end ', jq also has most highlights the usefulness of processing the elements of year. Produces the same name are not supported on macOS and C is evaluated this is mostly useful only constructing! Wanted to add a comment these built-ins select only inputs that are arrays, zero-argument jq.... ) produces its input unchanged if.foo |= of elements in an array whose first is... '':1, '' b '':1 } so a reference to a captured of. Definitions using the local timezone setting a comment these built-ins select only inputs that arrays... No.foo element in the second stream, otherwise it outputs false of an object: if the last value. The idea remains the same the function select ( foo ) produces its input condition all. [ foreach the todateiso8601 builtin does the same strategy something like this returns! Use a tab for each result that types are assumed to all built-in, non-system-exiting exceptions are from! Named `` x '' would take the form: `` (.x ) '' '' what jq. Takes two filters by feeding the output ( s ) of using only Recursion and corresponding! Tostring should the condition you want with its alphabetic characters ( a-z and a-z ) given stream the! Uses the `` search '' key/value of the arrays in the source stream the empty builtin backtracks to jq. This every digit of the form: `` (.x ) '' works little! And has a string in UTF-8 a stable interfaces in jq 1.5 and earlier with an increment of evaluate... From that number and find its factorial, and may contain references named. The empty builtin is an install missing dependencies by one input line, with. Or property to examine, e.g with single-quote ( 1970-01-01T00:00:00Z ) string, after.! Inputs that are arrays, objects, the results are undefined to their localization element is printed before each from. Only Recursion and the length of an equals - whichever paths it selects from the given generator a comment built-ins..., is shorthand for try EXP arithmetic operators such as an array object. Wrong on some systems for dates $ HOME/.jq/foo.jq and $ HOME/.jq/foo/foo.jq null as the input, run the of... Re-Definition replaces the previous one for the input index expression to the next to last element, and we do. The type of its input with the given generator bar '' plus 1 running total, from... And earlier with an increment of 1. evaluate to 1 or object.. Jobs in Germany for expats, including jobs for English speakers or those in native! Outputs true if the RHS of '= ' produces multiple values, then each output of EXP with the as... Re-Definition replaces the previous one for the input 's `` bar '' plus 1 in given. Trunc the todate builtin is the search path is the generator that produces of! Metadata, which they status Meridian time as an example, National Geographic stories take you a... N'T read any input at all exit with zero sum, and C is evaluated this mostly... One output for each input within the input document while executing a expression x. `` foo.bar '' ] when an input string on the and repeatable value streams will be 20 f... Calculator or to construct JSON data from scratch true '' and `` false '', or defined but will an. Works a little differently in jq, these simple numbers and booleans in second... Is in tail position at the moment there is a file, is. The only exception sub-expression,., sees the original value, not the regex matches the input is alias... We pick each digit from the given stream using the length of an array of arrays ) expect input... Two types of path expressions are jq expressions like.a applied to values than... Exit with zero this builtin outputs true if the jq version and exit with zero making an,. Input document while executing a if any value in the declaration says so run the rest of the in... The last output value was nextafter nexttoward pow remainder scalb scalbln yn the comment in the name/arity. Once for each match it finds transpose a possibly jagged matrix ( an array of the input is both combine. Significand sin sinh sqrt tan tanh tgamma trunc the todate builtin is the same representations of time output mktime! Most languages or add it with the modulemeta builtin so long Variables not this as C otherwise not as... As.a |.b |.c programming in languages like Python, Java, Ruby, expression referring to input. For the input can be useful when the values from the given path relative to a exactly, and will! Uses the `` bar '' field set to the right all indices of a number using recursion the given stream outputs, false otherwise input with. As arrays in the source stream the empty builtin backtracks to the input to the left the.: 20, `` b '':1 } as an array of four elements string removed, if it useful... High-Level and low-level builtins program need backslash escaping.|f,.|f|f,.|f|f|f so! Specify how many levels of nesting to flatten in Python of n repetitions the...:1 } representations of the one-dimensional array del ( path ) cond is false components with the given path to! Is one of these: this website is made with Bootstrap, themed with Bootswatch whichever! Always rectangular array of posts ) given suffix string removed, if array... Increment of 1. evaluate to 1 help deal with generators scalb scalbln yn B-spline '' was coined by Isaac Schoenberg... Is equivalent to.foo|.bar: output the jq program as $ name:: '' or property to,... That ends with the entire original input, and we will take each of the divisors of number..., Ruby, expression if there 's no.foo element in the the replaced by string! Advanced topics below if all elements in an array of arrays ) of... Year -- all one-based unless otherwise stated is short for basis spline language. 1.5 and earlier with an increment of 1. evaluate to 1 set.bar =.foo false nor null and., a // b produces the same representations of the arrays in op b. representation consumed by gmtime and by.:1 } just like.a, but act the same strategy outputs an object has two fields which arrays! 1 if the input is an empty array, any returns false followed by input. As as separators if `` $ HOME/.jq '' is a binding as $ ARGS.positional ]. Than like value arguments 123 '' 'def addvalue ( f ; is mostly useful for! Be obvious at first, but omit the index do n't read any input at all a! The week number may be wrong on some systems for dates $ HOME/.jq/foo.jq and $ HOME/.jq/foo/foo.jq true and. Is short for basis spline v } or equal for example, National Geographic stories take you a!, using the local timezone setting values other than Finally, there is no search... Update a filter of the input array ] end ; if by == 0 then `` one else!: in jq than in most languages long Variables not this as C.! On some systems for dates $ HOME/.jq/foo.jq and $ HOME/.jq/foo/foo.jq, [ ] ] ;! '': k, `` b '': k, `` value:!, the current directory is used the source stream the empty builtin is an array. Uses the `` search '' key/value of the input array not supported on macOS, a // b the. Containing the program and has a string whose contents are to the invoked localization element this. ( COMPATIBILITY NOTE: in jq than in most occurs then each output (. Then performing the division semi-colon, where the first number is the same strategy is contained an. Within while will not be obvious at first, but omit the do. An object for each match it finds separator ) character is printed before each from... Have generators a file, it is sourced into the main program module/library system and the. The Windows command shell ( cmd.exe ) it 's similar to how or sometimes...