GREP case insensitivity

italiansauce88 has asked for the wisdom of the Perl Monks concerning the following question:

my @bintext2 = grep {$_ =~ "$input"} @bintext;
[download]

Where $input is the <STDIN>, how can I make this grep search case insensitive?
The rest of the code is here:

#!usr/bin/perl -w
# nl.plx
use strict;

open FILE,"<$ARGV[0]";
my @foo = <FILE>;
my $lineno = 1;

print "Enter in search keyword: ";
my $input = <STDIN>;
chomp($input);

my @bintext = qx(strings.exe -n 4 Page.txt);
print "@bintext\n";
my @bintext2 = grep {$_ =~ "$input"} @bintext;
print "@bintext2\n";
[download]

Thank You!!!

Comment on GREP case insensitivity Select or Download Code

Replies are listed 'Best First'.
Re: GREP case insensitivity by ccn (Vicar) on Nov 13, 2008 at 20:36 UTC
`my @bintext2 = grep { /$input/i } @bintext;` [download] see perlre	[reply] [d/l]
Re: GREP case insensitivity by Corion (Patriarch) on Nov 13, 2008 at 20:37 UTC
See perlre. Also, you likely want to use real regular expressions in your match syntax and not strings: `my @bintext2 = grep { $_ =~ /$input/i } @bintext; # or even shorter my @bintext2 = grep { /$input/i } @bintext;` [download]	[reply] [d/l]
Re: GREP case insensitivity by duelafn (Parson) on Nov 13, 2008 at 23:59 UTC
There is a good chance that you would want to escape $input so that special regex characters match exactly, rather than taking on their special meaning. `my @bintext2 = grep { /\Q$input\E/i } @bintext;` [download] This way things like "*", "+", and "-" match literally. Good Day, Dean	[reply] [d/l]
Re^2: GREP case insensitivity by graff (Chancellor) on Nov 14, 2008 at 00:10 UTC
Then again, there's an equally good chance that the user wants the special regex characters to be applied as such, and not as literals. In that case, users can supply escapes and "\Q" (or not) according to their preference.	[reply]
Re: GREP case insensitivity by graff (Chancellor) on Nov 14, 2008 at 00:04 UTC
If you are using the grep function simply to grab the items in a list that match a particular pattern, you don't even need the curlies: `my @bintext2 = grep /$input/i, @bintext;` [download] (note the comma after the regex) You only need curlies if you are using grep with a code snippet (item is selected if the code returns true) -- e.g.: `my @bintext2 = grep { /$input/i and length()>20 } @bintext;` [download] (note: no comma after the code block)	[reply] [d/l] [select]
Re^2: GREP case insensitivity by jwkrahn (Abbot) on Nov 14, 2008 at 01:59 UTC
You only need curlies if you are using grep with a code snippet The reason your example needs curlies is because the `and` operator has lower precedence than the comma operator. If you use the `&&` operator then a comma works. `my @bintext2 = grep /$input/i && length > 20, @bintext;` [download]	[reply] [d/l] [select]
Re: GREP case insensitivity by Hue-Bond (Priest) on Nov 14, 2008 at 08:21 UTC
You can also do `grep { lc $_ eq lc $input }` -- David Serrano	[reply] [d/l]
Re^2: GREP case insensitivity by italiansauce88 (Initiate) on Nov 14, 2008 at 14:49 UTC
Worked like a charm! Thanks for all the help! Tim	[reply]