If you are concerned about the performance while reading the file into an array I would recommend doing some sample code and running it against a large file (say 100MB or more) to test the speed difference between doing: 
@array = <FILE>;

[download]
and doing: 
while(<FILE>) {
    push(@array, $_);
}

[download]
and run it multiple times to make sure you're not just getting the effect of the file being cached in memory.

I have found that while the version with the while loop *looks* longer it actually has always run faster in the tests I've done.

PS: a die message with your open statement like 

open (DF, "test.txt") || die "Can't read 'test.txt': $!\n"

[download]
is your friend, as are: 
use strict;
use warnings;

[download]
at the top of your script - I'd recommend using them - they will help you by saving you time finding what's causing errors and in the long run should also help you to write better code by teaching you good habits.

:o)

update: Thanks ChOas - I've fixed it. I always use the () brackets and || myself - and vaguely recalled (like you point out) that there *was* a difference between || and 'or'.

After having Dominus do a presentation to us the other week and finding I am in th habit of using () where I don't absolutely need to, I'd thought I'd not add them here where NeilF wasn't already using them... I've put them back on now :o)

running: 

perl -MO=Deparse -e 'open (DF, "test.txt") || die "Cant read test.txt\
+n";'

[download]
tells me I *could* write it: 
die "Can't read test.txt\n" unless open DF, 'test.txt';

[download]
but I won't :o)

In reply to Re: Perl always reads in 4K chunks and writes in 1K chunks... Loads of IO! by serf
in thread Perl always reads in 4K chunks and writes in 1K chunks... Loads of IO! by NeilF

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.