so it's more effective to say: 
next unless
        substr($file,0,6) eq 'AB DAT'
    and substr($file,-4)  eq '.doc'
;

[download]

A. That's not more effective. It's just as effective. It may be ever so slightly more efficient but the micro-optimization probably isn't really all that important.

B. It's verbose and harder to read at a glance than a simple regular expression is. This is probably more important than whatever small optimization you might get by using substr.

If the filename were in $_ I'd suggest next unless /^AB DAT/ and /\.doc/; which would be a good compromise.

I just noticed your first suggestion:

next unless $file =~ m/^ AB \s DAT .* \.doc $/x;

[download]
I think this case in particular would really be a good time to use a literal space instead of \s and avoid /x. In general, I think /x makes short regular expressions harder to read. Do you often use /x on short expressions and if so, what's your reasoning?

-sauoq
"My two cents aren't worth a dime.";

In reply to Re: Re: Reg Expression on file name by sauoq
in thread Reg Expression on file name by Anonymous Monk

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