The result is a Number, which gives the byte index in {haystack} of the last occurrence of the String {needle}. When {start} is specified, matches beyond this index are ignored. This can be used to find a match before a previous match:

:let lastcomma = strridx(line, ",")
:let comma2 = strridx(line, ",", lastcomma - 1)

The search is done case-sensitive. For pattern searches use match(). -1 is returned if the {needle} does not occur in {haystack}. If the {needle} is empty the length of {haystack} is returned. See also stridx(). Examples:

:echo strridx("an angry armadillo", "an")          3

When used with a single character it works similar to the C function strrchr().

Can also be used as a method:

GetHaystack()->strridx(needle)