Some people hate this, but I like it and it works. Obviously limitd by memory, but I've parsed 8Mb text files like this no problem.

This method may address issues if these are busy files. That is, leave the disk alone, do everything in RAM, then bother the disk when you're done.

(For the purists, only the salient features are included, not die or flock etc.) 

#slurp the files into arrays
open(FILE, 'filename_1');
@LINES_1 = <FILE>;
close(FILE);
open(FILE, 'filename_2');
@LINES_2 = <FILE>;
close(FILE);
open(FILE, 'filename_3');
@LINES_3 = <FILE>;
close(FILE);

# cycle through your file, pushing lines onto other files' arrays
for $i (0 .. $#LINES_1) {
     if (condition_a) {push(@LINE_2, $LINES_1[$i]);}}
     if (condition_b) {push(@LINE_3, $LINES_1[$i]);}}
}

# write new arrays to files
open(FILE, ">filename_2");
for my $i (0 .. $#LINES_2) {print FILE "$LINES_2[$i]";}
close(FILE);
open(FILE, ">filename_3");
for my $i (0 .. $#LINES_2) {print FILE "$LINES_3[$i]";}
close(FILE);

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In reply to Re: Re: Speed of opening and closing a file 1000s times by punchcard_don
in thread Speed of opening and closing a file 1000s times by seaver

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