It's not too clear just what kind of transformations you want to do, but the data looks like the fields are different enough to each take completely different treatment.

How about making an array of subroutines, each handling the transformations for the field with the corresponding index? 

my @xforms = (
    sub {
        $_[0] = $_[0] || 1;
    },
    sub {   # dummy, no transform
        $_[0];
    },
    sub {1},
    sub {
        $_[0] =~ s/foo/bar/;
        $_[0];
    },
    sub {1},
    sub {1},
    sub {1},
    sub {1},
);

while (<DATA>) {
    my @tmp = split ',';
    for (0 .. $#tmp) {
        $xforms[$_]->($tmp[$_]);
    }
    print join ',', @tmp;
}

[download]
So long as you don't use code tags, I can't tell where your data lines end or guess what you might want to do to them.

After Compline,
Zaxo

In reply to Re: how to so this string replacement elegantly by Zaxo
in thread how to so this string replacement elegantly by edwardt_tril

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


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.