At the simplest, you can use the ternary ? : operator to achieve this:

  my $lookfor = ($line =~ /TC/g) ? 'TC' : 26;
  print $lookfor;

[download]

This works when the expression is simple. When things start to get complicated, the operator tends to get lost in the rest of the code and it takes more time to decipher the meaning. In cases like these I'm fond of using the do statement:

  my $lookfor = do {
    if( $line =~ /^(\w{3})(\d{3})/ ) {
        my ($token, $repeat) = ($1, $2);
        $token x $repeat;
    }
    else {
       lc( substr( $line, 0, 4 ));
    }
  };

[download]

The beauty of this approach is that it reduces the scope of intermediate variables. In the above (contrived) example, the variables $token and $repeat are not visible outside the do block. This is a Good Thing.

The only gotcha to look out for is to remember the trailing semicolon on the do.

In reply to Re: Use variable outside if statement (use ? : or do {...}) by grinder
in thread Use variable outside if statement by Anonymous Monk

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.