As we mentioned near the beginning of this book, Perl is designed to be good at solving programming problems that are about 90% working with text and 10% everything else. So it's no surprise that Perl has strong text processing abilities, including all that we've done with regular expressions. But sometimes the regular expression engine is too fancy, and you'll need a simpler way of working with a string, as we'll see in this chapter.
a substring depends on where you have lost it. If you happen to have
lost it within a bigger string, you're in luck, because the
function can help you out.
Here's how it looks:
$where = index($big, $small);
Perl locates the first occurrence of the small string within the big
string, returning an integer location of the first character. The
character position returned is a zero-based value—if the
substring is found at the very beginning of the string,
it's one character later, the return value is
1, and so on. If the substring can't be
found at all, the return value is
-1 to indicate
that. In this example,
my $stuff = "Howdy world!"; my $where = index($stuff, "wor");
Another way you could think of the position number is the number of
characters to skip over before getting to the substring. Since
6, we know that we
have to skip over the first six characters of
$stuff before we find
index function will always report the ...