Hello Joma,

I’ll make three observations on the regex code shown:

  1. There’s no point in capturing to $2 if that capture is never used. It would be better to use a non-capturing group here:

    while ($line =~ m/"([^"\\]*(?:\\.[^"\\]*)*)",?|([^,]+),?|,/g) {
#                          ^^^
    push(@fields, defined($1) ? $1 : $2);
#                                    ^^

    [download]

    See perlretut#Non-capturing-groupings.

  2. When testing for definedness, Perl’s // (logical defined-or) operator is useful and elegant:

        push @fields, $1 // $2;

    [download]

    See perlop#Logical-Defined-Or.

  3. If you had use warnings at the head of your script (and you should!), you would get a Use of uninitialized value warning each time you try to print an array element whose value is undef. You can fix this easily by substituting an empty string:

        push @fields, $1 // $2 // '';

    [download]

Update: ++choroba for pointing out that the Branch Reset pattern (perlre#Extended-Patterns) is a more elegant option here.

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

In reply to Re^3: Parsing CSV file by Athanasius
in thread Parsing CSV file by Joma

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.