Function: RegexFindLast

RegexFindLast ( REGEX, STRING )

Finds the index of the last matching substring that matches the provided RegEx and returns it.

Parameters

Parameter	Type	Description
REGEX	VALUE(STRING)	The RegEx pattern to use.
STRING	VALUE(STRING)	The string to scan.

Returns

VALUE(INTEGER)

The index of the last match or -1 if not found.

What It Does

This function uses the provided RegEx pattern to find the last matching substring in the provided input string. This returns the starting index of the match if a matching substring is found, and -1 if nothing was matched. Both parameters are interpreted as strings before the scan.

If the RegEx pattern provided is an invalid or unparseable expression, this function will throw a FATAL cue and halt the module. To avoid this, you may want to pre-check the validity of the expressions you use with IsRegex().

Example

RegEx Function Example


world
{
    start()
    {
        textln(isRegex(`asdf\s\+`));	                // true
        textln(isRegex(`\`));			                // false
        textln("");
        
        s = "Apples and Oranges! 12345.67890";
        
        textln(regexFind(`[A-Za-z]+`, s));              // 0
        textln(regexFind(`[0-9]+`, s));                 // 20
        textln("");

        textln(regexFindLast(`[A-Za-z]+`, s));          // 11
        textln(regexFindLast(`[0-9]+`, s));             // 26
        textln("");

        textln(regexGet(`[A-Za-z]+`, s));               // "Apples"
        textln(regexGet(`[0-9]+`, s));                  // "12345"
        textln("");

        textln(regexGetLast(`[A-Za-z]+`, s));           // "Oranges"
        textln(regexGetLast(`[0-9]+`, s));              // "67890"
        textln("");

        textln(regexGetAll(`[A-Za-z]+`, s));            // ["Apples", "and", "Oranges"]
        textln(regexGetAll(`[0-9]+`, s));               // ["12345", "67890"]
        textln("");

        textln(regexMatches(`[A-Za-z]+`, s));           // false
        textln(regexMatches(`[A-Za-z]+`, "Apples"));    // true
        textln("");

        textln(regexSplit(`[\s]+`, s));                // ["Apples", "and", "Oranges!", "12345.67890"]
        textln(regexSplit(`[\s!\.]+`, s));            // ["Apples", "and", "Oranges", "12345", "67890"]
        textln("");

        textln(regexReplace(`[\s]+`, "", s));          // "ApplesandOranges!12345.67890"
        textln(regexReplace(`[\s!\.]+`, "==", s));    // "Apples==and==Oranges==12345==67890"

        quit;
    }
}

Additional Technical Notes

Because of the nature of RegEx, the search still scans the full string - only the last acceptable match is returned.

Note that when passing a literal string to this function, the backslash \ character is important in RegEx, so any use of it as part of the expression should be escaped: \\. For this reason, it may be better for readability's sake to use raw strings, like in the example above.

All RegExes in TAME are considered case-sensitive and match globally (the entirety of the input string used with it is potentially examined).

There are several resources on RegEx out there, such as www.regular-expressions.info and and a more interactive example at RegExr.com.