Tools

jq Joy: Sum Of Elements In An Array Or Object

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Hubert Klein Ikkink

jq is a powerful tool to work with JSON from the command-line. The tool has a lot of functions that makes our live easier. One of the functions is add which adds all elements in an array or values in an object. The function has no arguments. The elements in an array are added together if they are numbers and concatenated if they are strings. If the input is an object then the values are added together. When the input is an empty array or object then null is returned.

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jq Joy: Using String Interpolation

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Hubert Klein Ikkink

jq is a powerful tool to work with JSON from the command-line. The tool has a lot of functions that makes our live easier. With jq we can use expressions in strings that will be evaluated and inserted into the string value. This is called string interpolation. The expression is enclosed by parentheses and the first parenthesis is prefixed with a backslash: \(<expression>). The expression can be any valid jq expression and the result of the expression will be inserted into the string.

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jq Joy: Getting Keys From Object And Indices From Array

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Hubert Klein Ikkink

jq is a powerful tool to work with JSON from the command-line. The tool has a lot of functions that makes our live easier. For example we can use the keys and keys_unsorted functions to get the keys from an object. The function keys will return the keys in sorted order while keys_unsorted will return them in the original order from the object. With the same functions we can also get the indices of the elements in an array, but there is no sorting involved, so both functions return the same output.

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jq Joy: Using Default Values With The Alternative Operator

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Hubert Klein Ikkink

jq is a powerful tool to work with JSON from the command-line. The tool has a lot of functions and operators that makes our live easier. One of the operators we can use is the alternative operator // which allows us to specify default values. If the value on the left side of the operator // is empty, null or false then the value on the right side is returned, otherwise the value itself is returned. The operator can be used multiple times if we want to have multiple fallbacks for a value we are checking.

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