RE: Counting occurances of a pattern in a file

Untested, and should be treated as psuedocode:

use strict; # Always
use IO::File; # I like to localize filehandles.

sub CountPatternInFile
{
    my ( $filename, $pattern, $stop_pattern ) = @_;
    my $fh = IO::File->new( $filename ) or die $!;
    my $count = 0;
    while( <$fh> )
    {
        $count += s/($pattern)/$1/g
        last if m/$stop_pattern/;
    }
    close $fh or die $!;
    return $count;
}
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Comment on RE: Counting occurances of a pattern in a file Download Code

Replies are listed 'Best First'.
RE (tilly) 2: Counting occurances of a pattern in a file by tilly (Archbishop) on Aug 31, 2000 at 04:21 UTC
Don't use IO::File. Why not? Twice as slow as native handles. You don't need it. I have tripped over bugs when using IO::* that I didn't with regular IO. Don't remember the combination of things that hit it, but procedural IO worked and the other did not. If you want lexical filehandles use the technique that I did at RE (tilly) 1: Merging files. Or with 5.6 don't worry about it because handles autovivify for you. (Just part of the ongoing improvements. :-)	[reply]
RE: RE: Counting occurances of a pattern in a file by Adam (Vicar) on Aug 31, 2000 at 03:19 UTC
Or without a loop (also untested): `use strict; # Always use IO::File; # I like to localize filehandles. sub CountPatternInFile { local $/; my ( $filename, $pattern, $stop_pattern ) = @_; my $fh = IO::File->new( $filename ) or die $!; $_ = <$fh>; close $fh or warn $!; ($_) = split /$stop_pattern/; return s/($pattern)/$1/g; }` [download]	[reply] [d/l]