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Re^2: map versus for

by TheDamian (Priest)
on Aug 06, 2008 at 00:14 UTC ( #702524=note: print w/replies, xml ) Need Help??


in reply to Re: map versus for
in thread map versus for

...when you use map, most of your looping and list generation is being done in heavily optimized compiled C-code, not in interpreted Perl. So itís usually being done considerably faster.

Alas for the static nature of the printed word.

This assertion used to be true (back when I was first developing PBP in early 2004). I wouldn't have written it if the example I used hadn't confirmed the statement when benchmarked.

But in all the recent versions of Perl I currently have installed (5.8.3, 5.8.8, 5.10.0), a for outdoes the corresponding map on every test I can think to run. Needless to say, PBP edition 2 will be updated to reflect the current behaviours, but that doesn't fix the thousands of existing copies with that overconfident assertion in them. Sigh. One lives and learns.

Damian

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Re^3: map versus for
by dragonchild (Archbishop) on Aug 06, 2008 at 02:17 UTC
    Wouldn't this be because of the improvements made in 5.8 re: more efficient aliasing of the loop variable?

    My criteria for good software:
    1. Does it work?
    2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

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