Re: Don't want to match nothing

Then check that $b has a value. You could just use $b as the test, ie.

if( $b and $a =~ /$b/ ) { do this }
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but I wouldn't do that in case $b == 0. I also wouldn't use eq in case $b is numeric or == in case $b is a string. So do something like,

if ($b !~ /^$/ and $a =~ /$b/) { do this }
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RE: Re: Don't want to match nothing by splinky (Hermit) on Jul 06, 2000 at 07:06 UTC
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 }` Woof	[reply] [d/l] [select]
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]