find

Given two String parameters input and pattern, searches for the occurrence of pattern within input and returns the first match or None if there are no matches. pattern is a regular expression and is evaluated as a POSIX Extended Regular Expression (ERE).

Note that regular expressions are written using regular WDL strings, so backslash characters need to be double-escaped. For example:

String? first_match = find("hello\tBob", "\\t")

Parameters

1. String: the input string to search.
2. String: the pattern to search for.

Returns: The contents of the first match, or None if pattern does not match input.

Example: test_find_task.wdl

version 1.2
workflow test_find {
  input {
    String in = "hello world"
    String pattern1 = "e..o"
    String pattern2 = "goodbye"
  }
  output {
    String? match1 = find(in, pattern1)  # "ello"
    String? match2 = find(in, pattern2)  # None
  }  
}

{}

{
  "test_find.match1": "ello",
  "test_find.match2": null
}