How to use the textmatch function?

How to use the textmatch function?

textmatch is a function which evaluates the specified regular expression against a given string attribute. It returns true if the string contains the pattern. It uses double backslash (\\) to escape.

Syntax:

textmatch(string_attribute, regex_pattern)

Example:

azuread oauth2permissiongrant should-not-have textmatch(scope, "AppRoleAssignment.ReadWrite.All") = true

Regular Expression Constraints used with textmatch:

• ^ : check match at the beginning of the string

  Example String	Pattern	Match	Note
  abc	^a	Yes	The match is successful because the alphabet “a” is found at the beginning of the String.
  bac	^a	No	The match is unsuccessful because the alphabet “a” is not found at the beginning of the String.

• $ : check match at the end of the string

Example String	Pattern	Match	Note
abc	a$	No	The match is unsuccessful because the alphabet “a” is not found at the end of the String.
bac	c$	Yes	The match is successful because the alphabet “c” is found at the beginning of the String.

Metacharacters used with textmatch:

• | : alternation or choice between elements.

  Example String	Pattern	Match	Note
  a	a|b	Yes	The match is successful because the pattern “a|b” has “a” string.
  a	c|d	No	The match is unsuccessful because the pattern “c|d” does not have “a” string.

• [ ] : specifies a character class.

  • If two characters in the list are separated by -, this is shorthand for the full range of characters between those two.

  • If the list begins with ^, it matches any single character not from the rest of the list.

    Example String	Pattern	Match	Note
    a	[abc]	Yes	The match is successful because “a” is found in the pattern.
    d	[abc]	No	The match is unsuccessful because “d” is not found in the pattern.
    5	[0-9]	Yes	The match is successful because “5” is found in the decimal digit series between 0 to 9.
    a	[a0-9]	Yes	The match is successful because “a” is found in the pattern of a and 0 to 9 decimal digit series.
    z	[a-z0-9]	Yes	The match is successful because “z” is found in the pattern of a to z letters and 0 to 9 decimal digit series.
    A	[^a-z0-9]	Yes	The match is successful because the string is any character that is not a lowercase a to z letters or 0 to 9 decimal digit series.

• * : finds a sequence of none to multiple matches

  Example String	Pattern	Match	Note
  x	x*	yes	The match is successful because “x” is found in the pattern.
  a	x*	yes	The match is successful because no “x” is found in the pattern.
  xxxx	x*	yes	The match is successful because “x” is found in the pattern multiple times.

• + : a sequence of one or more matches

  Example String	Pattern	Match	Note
  x	x+	yes	The match is successful because “x” is found in the pattern.
  a	x+	no	The match is unsuccessful because “x” is not found in the pattern.
  xxxx	x+	yes	The match is successful because “x” is found multiple times in the pattern.

• ? : a sequence of none or one match

  Example String	Pattern	Match	Note
  x	x?	yes	The match is successful because “x” is found in the pattern.
  a	x?	yes	The match is successful because no “x” is found in the pattern.
  xxxx	x?	yes	The match is successful because “x” is found in the pattern.

• {m} : a sequence of exactly m matches of the atom

  Example String	Pattern	Match	Note
  x	x{2}	no	The match is unsuccessful because “x” is not found 2 times in the pattern.
  xx	x{1}	yes	The match is successful because “x” is found 1 time in the pattern.
  a	x{0}	yes	The match was successful. The {0} causes the “x” to be ignored, the pattern is essentially an empty string.

• {m,} : a sequence of m or more matches

  Example String	Pattern	Match	Note
  x	x{1,}	yes	The match is unsuccessful because “x” is found 1 time in the pattern.
  x	x{2,}	no	The match is unsuccessful because “x” is not found 2 times in the pattern.
  x	x{0,}	yes	The match was successful. The {0} causes the “x” to be ignored, the pattern is essentially an empty string.

• {m, n} : a sequence of m through n (inclusive) matches, m cannot exceed n

  Example String	Pattern	Match	Note
  x	x{1,2}	yes	The match is successful because the string contains “x” and the pattern requires the same to be matched.
  x	x{2,3}	no	The match is unsuccessful because the string contains only “x”, while the pattern requires at least “xx” to be matched.
  xxxx	x{1,2}	yes	The match is successful because the string contains “xx” and the pattern requires the same to be matched.

  Class-shorthand escapes used with textmatch:

\\d	Match any digit
\\s	Matches any whitespace character
\\w	Matches any word character
\\D	Match any non-digit
\\S	Matches any non-whitespace character
\\W	Matches any non-word character