map

Description

Apply the expr to every element in the elements array and return the array of results. An elements of length N will produce a return array of length N.

Unlike a projection, ([\*].bar), map() will include the result of applying the expr for every element in the elements array, even if the result if null.

Arguments

Required

Name	Type	Description
expr	expression
elements	array[any]

Returns

Type: array[any]

Examples

search(map(&foo, array), {"array":[{"foo":"a"},{"foo":"b"},{},[],{"foo":"f"}]}) → ["a","b",null,null,"f"]

search(map(&[], @), [[1,2,3,[4]],[5,6,7,[8,9]]]) → [[1,2,3,4],[5,6,7,8,9]]

search(map(&[], array), {"array":[[1,2,3,[4]],[5,6,7,[8,9]]]}) → [[1,2,3,4],[5,6,7,8,9]]

Given the following JSON input:

{
  "people": [
    {
      "a": 10,
      "b": 1,
      "c": "z"
    },
    {
      "a": 10,
      "b": 2,
      "c": null
    },
    {
      "a": 10,
      "b": 3
    },
    {
      "a": 10,
      "b": 4,
      "c": "z"
    },
    {
      "a": 10,
      "b": 5,
      "c": null
    },
    {
      "a": 10,
      "b": 6
    },
    {
      "a": 10,
      "b": 7,
      "c": "z"
    },
    {
      "a": 10,
      "b": 8,
      "c": null
    },
    {
      "a": 10,
      "b": 9
    }
  ],
  "empty": []
}

Expression	Result
map(&a, people)	[10,10,10,10,10,10,10,10,10]
map(&c, people)	["z",null,null,"z",null,null,"z",null,null]
map(&a, badkey)	ERROR: invalid-type
map(&foo, empty)	[]

Given the following JSON input:

{
  "array": [
    {
      "foo": {
        "bar": "yes1"
      }
    },
    {
      "foo": {
        "bar": "yes2"
      }
    },
    {
      "foo1": {
        "bar": "no"
      }
    }
  ]
}

Expression	Result
map(&foo.bar, array)	["yes1","yes2",null]
map(&foo1.bar, array)	[null,null,"no"]
map(&foo.bar.baz, array)	[null,null,null]