Your for loop is effectively a map: 

@l = map { ... } glob("*.gz")

[download]

Does that help?

BTW, the `shell stuff` will give you a scalar with embedded newlines, not a list of lines of text which is what I presume you want. You'll be better of using open(my $fh, '-|', "zcat $_") instead and read a line at a time, and translate the little sed snippet into perl.

Finally, why do you think that rewriting the code will save memory or make it faster? And do you know that it actually needs to be made faster? Have you profiled your code?

In reply to Re: add/replace map result into existing hash by DrHyde
in thread add/replace map result into existing hash by fredo2906

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.