Re: how to avoid opening and closing files

Can I just open once a file and remove all lines together having words stored in words.txt?

See map and grep

(and specially "grep (!/regex/) the_file", where regex should match words stored in words.txt

my @X;
while(<INFILE>){
 push @X,(split(/\s+/,$_))[0];} 
### choosing particular column and pushing all its values in single ar
+ray
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I guess that a hash (%X) could be better here, but if you want an array, think in an unique sorted list or so. The idea is to avoid duplicates.