IMHO, yes. The for version doesn't build a (possibly huge) list of the form ("x",1,"y",1,...) and then populate the hash; it just populates the hash. I suspect my "slice" version is the fastest... and: 

use Benchmark;
@arr=('file.html')x1024;
timethese( -3, {
    'Slice' => '%x=();@x{@arr}=(1)x@arr',
    'For' => '%x=();for(@arr){$x{$_}=1}',
    'Map' => '%x=map{$_=>1}@arr'
} );
__END__
Benchmark: running For, Map, Slice, each for at least 3 CPU seconds...
   For: 3 secs (3.13 usr + 0.00 sys = 3.13 CPU) @ 707.72/s (n=2218)
   Map: 3 secs (3.14 usr + 0.00 sys = 3.14 CPU) @ 96.98/s (n=305)
 Slice: 4 secs (3.14 usr + 0.00 sys = 3.14 CPU) @ 1074.72/s (n=3380)

[download]

...it is (for at least one case). So "slice" is 50% faster than "for" which is much faster than "map" (with tilly's patch, "map" will probably still be slower than the others, but not nearly that slow).

        - tye (but my friends call me "Tye")

In reply to RE: RE: RE: List non-matching files by tye
in thread List non-matching files by fundflow

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.