Er, hi.

It is true that I will weep with joy when the day arrives that I can answer more PerlMonk questions than I post. I'll gnash teeth, rend clothes, and some real Bible-style celebrating will go on. But alas, that day is not today. So...

I've seen benchmarks that indicate line-at-a-time file reading is not as efficient as slurping up the whole dad-gum thing into an array and stepping through it... depending on file size. Not hard to believe. So does anyone care to venture a guess (or happen to know) at approximately what file size method B will be more efficient (and quicker, naturally) than method B? Or, am I dead wrong, and one method is ALWAYS more efficient?

The idea is to find a listing in a newline-delimited file, pretty standard stuff, really (forgive the sloppy example code):

# METHOD A:
# whole file slurp and split

$him = "";
$enlightenment = "joy";
$trying = "oops";
@fileContents = "";

open(TEST, "test.txt") or die $trying;
local $/ = undef;
@fileContents = <TEST>;
close(TEST);

foreach (@fileContents) {
  my ($person, $wisdom) = split /:/, $_, 2;
  if ($wisdom eq $enlightenment) {
    $him = $person;
    last;
  }
}

# METHOD B:
# line-at-a-time

open (TEST, "test.txt") or die $trying;
$/ = "\n";
while (&lt;TEST&gt;) {
  my ($person, $wisdom) = split /:/, $_, 2;
  if ($wisdom eq $enlightenment) {
    $him = $person;
    last;
  }
}

[download]
Thanks for any info you've got.

Alan "Hot Pastrami" Bellows
-Sitting calmly with scissors-

In reply to File reading efficiency and other surly remarks by Hot Pastrami

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