Also sprach Aristotle:
I'm trying a simple 'if ($a =~ $b)' function, but it doesnt seem to
work, when clearly $b is contained in $a. Is there any particular
reason why a =~ expression wouldnt work correctly ?
ie trying to match ". Palms and soles, of: (2)" in ". Palms and soles,
of: (2) HYPER. LED."
If all you want to do is checking whether one string is contained in the
other, you'd be better off using index():
if (index($a, $b) != -1) {
...
}
The reason why your regex approach doesn't work as you expect is that
your string $b contains characters with a special meaning in regex-ish
context, most notably '.', '(' and ')'. This becomes more obvious when
you use the content of $b literally as a pattern:
". Palms and soles, of: (2) HYPER. LED." =~ /. Palms and soles, of: (2)/;
^ ^ ^
The special characters are marked. The pattern matches strings which
- begin with any character (excluding newline)
- followed by the string ' Palms and soles, of: '
- followed by '2' which is captured in $1
You can tell perl to take the pattern as a literal string without paying
attention to any regex meta-characters:
$a =~ /\Q$b/;
The \Q assertion treats anything that follows (up to an optional \E end
marker) literally.
Tassilo
