indexof_regex()

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel

Returns the zero-based index of the first occurrence of a specified lookup regular expression within the input string.

See indexof().

Syntax

indexof_regex(string,match[,start[,length[,occurrence]]])

Learn more about syntax conventions.

Parameters

Name	Type	Required	Description
string	string	✔️	The source string to search.
match	string	✔️	The regular expression lookup string.
start	int		The search start position. A negative value will offset the starting search position from the end of the string by this many steps: abs(start).
length	int		The number of character positions to examine. A value of -1 means unlimited length.
occurrence	int		The number of the occurrence. The default is 1.

Returns

The zero-based index position of match.

• Returns -1 if match isn't found in string.
• Returns null if:
  • start is less than 0.
  • occurrence is less than 0.
  • length is less than -1.

Note

• Overlapping matches lookup aren't supported.
• Regular expression strings may contain characters that require either escaping or using @'' string-literals.

Examples

Run the query

print
    idx1 = indexof_regex("abcabc", @"a.c"), // lookup found in input string
    idx2 = indexof_regex("abcabcdefg", @"a.c", 0, 9, 2),  // lookup found in input string
    idx3 = indexof_regex("abcabc", @"a.c", 1, -1, 2),  // there's no second occurrence in the search range
    idx4 = indexof_regex("ababaa", @"a.a", 0, -1, 2), // Matches don't overlap so full lookup can't be found 
    idx5 = indexof_regex("abcabc", @"a|ab", -1)  // invalid start argument

Output

idx1	idx2	idx3	idx4	idx5
0	3	-1	-1