Re: Going through a big file

> First I tried the obvious

open in, shift @ARGV; for(<in>){
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Obvious?

You will hardly find any example in the perldocs ever trying this.

Rather

open in, shift @ARGV; 
while (<in>){
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or better

open my $in, '<', shift @ARGV; 
while (my $line = <$in>){
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your code is semantically equivalent to

my @temp_list=<in>;
for(@temp_list){
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slurping the whole file as a first step.

for expects a list and evaluates in list contextš, so it's greedily swallowing all at once.

But while iterates in scalar context, that is line by line (as defined by '$/')

Cheers Rolf

š) with a little magical exception in recent Perl versions (>= 5.8 ?) regarding ranges, which isn't relevant here