RE: Re: Don't want to match nothing

Actually, ne should be fine, whether $b is numeric or not, and it's more efficient than a regex.

if ($b ne '' and $a =~ /$b/) { do this }

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RE: RE: Re: Don't want to match nothing by Adam (Vicar) on Jul 06, 2000 at 22:26 UTC
You are right. I come from a C++ back ground, so I don't use `ne` or `eq` much, so I just figured that if you get the warning for `==` the you would get it in the reverse direction with `eq`. But since perl will happily convert a number to a string, the problem doesn't exist. For added fun I benchmarked the difference between the regex and `ne`: `Y:\>perl -MBenchmark -we "print timethese( 10_000_000, {Regex, '$_=0; +print q[] if $_ !~ /^$/', NotEq, '$_=0; print q[] if $_ ne qq[]' } )" Benchmark: timing 10000000 iterations of NotEq, Regex... NotEq: 27 wallclock secs (26.41 usr + 0.00 sys = 26.41 CPU) @ 37 +8658.79/s (n=10000000) Regex: 37 wallclock secs (36.69 usr + 0.00 sys = 36.69 CPU) @ 27 +2531.55/s (n=10000000) HASH(0x8c134b0)` [download]	[reply] [d/l]

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RE: RE: Re: Don't want to match nothing
by Adam (Vicar) on Jul 06, 2000 at 22:26 UTC

ne

eq

==

eq

ne

Y:\>perl -MBenchmark -we "print timethese( 10_000_000, {Regex, '$_=0; 
+print q[]
if $_ !~ /^$/', NotEq, '$_=0; print q[] if $_ ne qq[]' } )"
Benchmark: timing 10000000 iterations of NotEq, Regex...
     NotEq: 27 wallclock secs (26.41 usr +  0.00 sys = 26.41 CPU) @ 37
+8658.79/s
(n=10000000)
     Regex: 37 wallclock secs (36.69 usr +  0.00 sys = 36.69 CPU) @ 27
+2531.55/s
(n=10000000)
HASH(0x8c134b0)
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