perl function rindex

The rindex function in Perl is used to find the last occurrence of a substring within a string, and return the position of the last character of the substring.

Here's an example of using rindex:

my $string = "The quick brown fox jumps over the lazy dog";
my $position = rindex $string, "fox";
print "$position\n"; # prints 16

In this example, the rindex function is used to find the position of the last occurrence of the substring "fox" within the string $string. The function returns the position of the last character of the substring, which is 16.

If the substring is not found in the string, the function returns -1. Here's an example:

my $string = "The quick brown fox jumps over the lazy dog";
my $position = rindex $string, "cat";
print "$position\n"; # prints -1

In this example, the rindex function is used to find the position of the last occurrence of the substring "cat" within the string $string. Since "cat" is not found in the string, the function returns -1.

Note that rindex is case sensitive. If you want to perform a case-insensitive search, you can convert the string and the substring to lowercase or uppercase before calling rindex.