I just did a quick test of opening a small file 500 times using method A, then grepping, and method B and using a match. Results of my benchmark:

Method A:
1 wallclock secs ( 0.16 usr + 0.02 sys = 0.18 CPU)

Method B:
0 wallclock secs ( 0.04 usr + 0.03 sys = 0.07 CPU)

Results may vary, try it yourself to see what you get. Not very surprising since Method A will need to populate an array, the loop through it and match. Method B just does the match.

UPDATE: Out of curiosity I did Method A withought building an array and simply grepping from the open filehandle. Small difference:
0 wallclock secs ( 0.12 usr + 0.03 sys = 0.15 CPU)

Cheers,
KM

In reply to Re: File slurping efficiency by KM
in thread File slurping efficiency by Hot Pastrami

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.