Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I've a simple little script that pads leading '0' characters (max 5 characters) to the last field of a csv file.

I just wondered if this could be turned into a one-liner? 

open FH,"< $ARGV[0]" or die $!;

while (<FH>) {
        my ($pre, $last) = $_ =~ m/(.*),(\w+)/;
        $last = substr(("0" x 5) . $last, -1 * 5, 5);
        print "$pre,$last\n";
}
close FH;

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Replies are listed 'Best First'.
Re: one liner?
by BrowserUk (Patriarch) on Aug 03, 2012 at 12:24 UTC

    Yes :) 

    C:\test>copy con in.csv
123,456
789,123
135,780
^Z
        1 file(s) copied.

C:\test>perl -F, -aple"$_ = join ',', $F[0], sprintf '%05d',$F[1]" in.
+csv
123,00456
789,00123
135,00780

    [download]
    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.

    The start of some sanity?
[reply]
[d/l]
      I forgot about sprintf being able to do that. Thanks.

      Though that solution won't work for a file with more columns.

[reply]
        Though that solution won't work for a file with more columns.

        This will:

        perl -F, -aple"$F[-1]=sprintf'%05d',$F[-1]; $_=join',',@F" in.csv

        [download]
        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.

        The start of some sanity?
[reply]
[d/l]
        perl -F, -aple"$_ = join ',', @F[0 .. $#F-1], sprintf '%05d',$F[-1]" in.csv

        This works even if each line has a different number of fields.

        CountZero

        A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

        My blog: Imperial Deltronics
[reply]
[d/l]
Re: one liner?
by jwkrahn (Abbot) on Aug 03, 2012 at 15:15 UTC 
    perl -lpe's/([^,]+)$/ sprintf "%05s", $1 /e' yourfile

    [download]
[reply]
[d/l]

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