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How can I find the first position of a substring case-insensitively?

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Contributed by ChilliHead on Dec 01, 2000 at 15:25 UTC
Q&A  > strings


Description:

I'm using index($mystr,"a") but I want to be able to check for "A" as well as "a".

Is it possible to make index case insensitive?

Answer: How can I find the first position of a substring case-insensitively?
contributed by eg

The easiest thing to do would be to use lc on $mystr like so:

  my $index = index( lc( $mystr ), "a" );
Edited by Russ: Combined posts by ambiguous, tektsu, kilinrax, ariels, and tenatious into one
Answer: How can I find the first position of a substring case-insensitively?
contributed by ambrus

You could use regexps, like this:

$needle = "a"; $haystack =~ /\Q$needle\E/i; $index = $-[0];
this works even if $needle has regexp-metacharacters in it.

But @- exists only in newer perls (from 5.6.1 I think). In perl 5.005 you could use something like

$needle = "a"; $haystack =~ /\Q$needle\E/i; $index = pos($haystack)-length($needle);
or
$needle = "a"; $haystack =~ /\Q$needle\E/i; $index = length($`);
but note that $` makes perl slower.

Whitespace added by tye

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