### Re^8: Undefined vs empty string

by Tux (Abbot)
 on Jun 05, 2013 at 12:32 UTC ( #1037196=note: print w/replies, xml ) Need Help??

in reply to Re^7: Undefined vs empty string
in thread Undefined vs empty string

How does my defined-or solution compare on your system?

Where did I omit the empty string in

foreach \$a (undef, "", 0, 1, "x" x 60) {

?

update new bench from your example. (my dor outperforms the other two consistently)

```\$ cat test.pl
use strict;
use Benchmark qw[ cmpthese ];

our @tests = (
(undef)  x 1000,
("")     x 1000,
(chr(0)) x 1000,
(0)      x 1000,
(1)      x 1000,
("fred") x 1000,
);
cmpthese -1, {
a => q[ !(defined && length() ) and 1 for @tests; ],
b => q[ !defined || \$_ eq ""    and 1 for @tests; ],
c => q[ (\$_ // "") eq ""        and 1 for @tests; ],
};
\$ repeat 5 perl test.pl
Rate    b    a    c
b 1950/s   -- -18% -33%
a 2379/s  22%   -- -18%
c 2901/s  49%  22%   --
Rate    b    a    c
b 1950/s   -- -22% -33%
a 2511/s  29%   -- -13%
c 2901/s  49%  16%   --
Rate    b    a    c
b 1950/s   -- -23% -32%
a 2536/s  30%   -- -12%
c 2875/s  47%  13%   --
Rate    b    a    c
b 1914/s   -- -22% -32%
a 2466/s  29%   -- -12%
c 2801/s  46%  14%   --
Rate    b    a    c
b 1950/s   -- -23% -32%
a 2536/s  30%   -- -12%
c 2875/s  47%  13%   --

Enjoy, Have FUN! H.Merijn

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Re^9: Undefined vs empty string
by BrowserUk (Pope) on Jun 05, 2013 at 13:06 UTC
Where did I omit the empty string in

Damn. My eyes are getting like an old CRT. They are taking longer and longer to warm up in the mornings :)

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

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