Beefy Boxes and Bandwidth Generously Provided by pair Networks
Syntactic Confectionery Delight
 
PerlMonks  

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??
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);

In reply to Optimizing perl code performance by usertest

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this?Last hourOther CB clients
Other Users?
Others examining the Monastery: (3)
As of 2024-03-29 07:26 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found