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$match

$match(string?, pattern, limit?) -> array<object>
Compact type signature<s-f<s:o>n?:a<o>>

If string is omitted, the current context value is used.

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Text

Source: JSONata

Documentation​

Applies the str string to the pattern regular expression and returns an array of objects, with each object containing information about each occurrence of a match withing str.

The object contains the following fields:

  • match - the substring that was matched by the regex.
  • index - the offset (starting at zero) within str of this match.
  • groups - if the regex contains capturing groups (parentheses), this contains an array of strings representing each captured group.

It is an error if str is not a string.

Examples​

Basic usage​

$match("ababbabbcc",/a(b+)/) =>

[
  {
    "match": "ab",
    "index": 0,
    "groups": ["b"]
  },
  {
    "match": "abb",
    "index": 2,
    "groups": ["bb"]
  },
  {
    "match": "abb",
    "index": 5,
    "groups": ["bb" ]
  }
]

Extract a code-shaped token (with capturing groups)​

Input

This example uses the free-text-notes example input. The expression reads the second note and extracts a code-shaped token with one capture group.

Example input

JSON
[
  "  follow-up recommended in 2 weeks  ",
  "reports intermittent headache; DX-001 noted",
  "plan PLAN-100: confirm eligibility for mbr-3001",
  "lab LAB-1002 flagged as HIGH; repeat test",
  "pat-0001: patient prefers morning appointments",
  "normalize   multiple   spaces"
]

Expression

$match($[1], /DX-(\d{3})/)

Result

{
  "match": "DX-001",
  "index": 31,
  "groups": ["001"]
}