Hello ovedpo15,

In Perl, a function’s return value(s) may be different depending on the context in which the function is called. (Whether they are or not depends on the internal details of the function itself.) The statement my $value = $row =~ /.*,(.*)/; calls the regex operator m// in scalar context, so it returns true if the match succeeds and false if it fails. But in the statement my ($value) = $row =~ /.*,(.*)/; the parentheses around $value put the call to m// into list context and a list of the matches is returned.

By contrast, the substitution operator s/// returns the number of substitutions made regardless of the calling context. But you can change this behaviour by adding an /r modifier to the substitution. This creates a copy of the string (in this case $row), applies the substitutions (if any) to the copy, and returns that copy. E.g.

my $row = 'a,b,c,d,15';
my $str = $row =~ s/,[^,]*$//r;    # $str now contains 'a,b,c,d'

[download]

See the sections m/PATTERN/msixpodualngc and s/PATTERN/REPLACEMENT/msixpodualngcer in perlop#Regexp-Quote-Like-Operators.

Hope that helps,

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

In reply to Re: difference in regex by Athanasius
in thread difference in regex by ovedpo15

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.