usertest has asked for the wisdom of the Perl Monks concerning the following question:
We have a requirement to read a source file, and for every row, apply some transformations and write to a output file. The code is however taking a long time approximately 25 seconds for processing a 500MB file. Please suggest if we can apply some performance improvements.
#!/usr/bin/perl use strict; use warnings; use POSIX qw(strftime); my $infile=$ARGV[0]; my $outfile=$ARGV[1]; open(DATAIN,"<$infile"); open(DATAOUT,">$outfile"); while(<DATAIN>) { my($line)=$_; chomp($line); my @Fields = split(',', $line,9); my $X=$Fields[8]; my $Y = substr $X,0,10; my $A = strftime "%M,%Y,%m,%d,%H,%j,%W,%u,%A", gmtime $Y; my $B = substr($A, 0, index($A, ',')); my $C = int($B/5); my $D = int($B/15); print DATAOUT $line,",",$Y,",",$A,",",$C,",",$D,"\n"; } close(DATAIN); close(DATAOUT);
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Replies are listed 'Best First'. | |
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Re: Optimizing perl code performance
by MidLifeXis (Monsignor) on Aug 14, 2015 at 17:57 UTC | |
by BillKSmith (Monsignor) on Aug 15, 2015 at 01:03 UTC | |
Re: Optimizing perl code performance
by enemyofthestate (Monk) on Aug 14, 2015 at 20:56 UTC | |
Re: Optimizing perl code performance
by Anonymous Monk on Aug 14, 2015 at 18:03 UTC | |
Re: Optimizing perl code performance
by Intermediate Dave (Novice) on Aug 15, 2015 at 03:10 UTC | |
by QM (Parson) on Aug 17, 2015 at 09:33 UTC | |
Re: Optimizing perl code performance
by flexvault (Monsignor) on Aug 14, 2015 at 17:26 UTC | |
by usertest (Initiate) on Aug 14, 2015 at 17:38 UTC | |
Re: Optimizing perl code performance
by marioroy (Prior) on Aug 15, 2015 at 14:48 UTC | |
by marioroy (Prior) on Aug 15, 2015 at 15:40 UTC | |
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