Upper case and chomp

TechFly has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Upper case and chomp by wind (Priest) on Feb 09, 2011 at 20:58 UTC
chomp returns the total number of characters removed, either 1 or 0, so your equality test will always fail. Just split up your efforts: `my @listaccountlocked = split "=", $accountlocked; chomp($listaccountlocked[1]); if (uc($listaccountlocked[1]) eq "TRUE") {` [download] - Miller	[reply] [d/l]
Re: Upper case and chomp by kennethk (Abbot) on Feb 09, 2011 at 21:01 UTC
As documented in chomp, It returns the total number of characters removed from all its arguments. This means you are using that incorrectly. Rather than using eq, I would suggest using a regular expression, like my @listaccountlocked = split("=", $accountlocked); if ($listaccountlocked[1] =~ /^true$/i) { system("chuser account_locked='false' $username"); print(`lsuser -a account_locked $username`); } else { print("\nThe account $username is not locked\n\n"); } [download] where `$` will ignore a trailing newline in reporting a match.	[reply] [d/l] [select]
Re^2: Upper case and chomp by roboticus (Chancellor) on Feb 10, 2011 at 15:22 UTC
I prefer using uc and a string compare like the OP suggested. I did a quick benchmark, and it looks like it's faster (negligible if no strings match, roughly double the speed if they all match. `if (uc($listaccountlocked[1]) eq 'TRUE) {` [download] Trivial benchmark: Read more... (2 kB) ...roboticus When your only tool is a hammer, all problems look like your thumb.	[reply] [d/l] [select]
Re^3: Upper case and chomp by kennethk (Abbot) on Feb 10, 2011 at 17:09 UTC
You have not used a fair test: note that my regular expression included the Metacharacters `^` and `$`. If I reconfigure your tests to consider this factor and swap to: `sub regex { my $cnt=0; for (@words) { ++$cnt if /^abcb$/i; } return $cnt; }` [download] I get the output: `In 4096 words, 16 are 'abcb' Rate uccmp regex uccmp 1192/s -- -5% regex 1255/s 5% -- In 4096 words, 0 are 'abcb' Rate uccmp regex uccmp 1225/s -- -3% regex 1264/s 3% -- In 4096 words, 4096 are 'abcb' Rate regex uccmp regex 970/s -- -23% uccmp 1260/s 30% --` [download] which obviously compares much better. This still does not consider that the string compare require a chomp which the regular expression does not. Modifying your benchmark to consider this: Read more... (2 kB) yields the results: `In 4096 words, 16 are 'abcb' Rate uccmp regex uccmp 812/s -- -32% regex 1197/s 47% -- In 4096 words, 0 are 'abcb' Rate uccmp regex uccmp 861/s -- -31% regex 1255/s 46% -- In 4096 words, 4096 are 'abcb' Rate uccmp regex uccmp 856/s -- -11% regex 964/s 13% --` [download] which I think clearly favors the regular expression. In addition, if you really wanted to squeeze out performance, you could skip the split in the OP as well: Read more... (2 kB) which yields: `In 4096 words, 16 are 'abcb' Rate uccmp regex uccmp 200/s -- -74% regex 767/s 283% -- In 4096 words, 0 are 'abcb' Rate uccmp regex uccmp 200/s -- -74% regex 756/s 278% -- In 4096 words, 4096 are 'abcb' Rate uccmp regex uccmp 206/s -- -66% regex 603/s 193% --` [download] Update: As ikegami points out, I failed to localize the arrays to the test routines, so there were a large number of no-ops. Fixing that with the code `my @words = @words` added where appropriate reduced margins but maintained ordering. I suspect that is just a function of the linear overhead of copying the large arrays. If this is incorrect, I would appreciate insight.	[reply] [d/l] [select]
Re^4: Upper case and chomp by ikegami (Patriarch) on Feb 10, 2011 at 19:12 UTC
Re^4: Upper case and chomp by roboticus (Chancellor) on Feb 10, 2011 at 22:57 UTC
Re^3: Upper case and chomp by hbm (Hermit) on Feb 10, 2011 at 16:12 UTC
Another option is string escapes: `if ("\U$listaccountlocked[1]" eq 'TRUE') {` [download] I added another sub to your benchmark: `sub slashU { my $cnt=0; for (@words){ ++$cnt if "\U$_" eq 'ABCB'; } return $cnt; }` [download] But it didn't fare very well: `In 4096 words, 16 are 'abcb' Rate slashU uccmp regex slashU 321/s -- -18% -26% uccmp 390/s 21% -- -10% regex 435/s 36% 12% -- In 4096 words, 0 are 'abcb' Rate slashU uccmp regex slashU 328/s -- -17% -25% uccmp 397/s 21% -- -10% regex 439/s 34% 11% -- In 4096 words, 4096 are 'abcb' Rate regex slashU uccmp regex 266/s -- -6% -18% slashU 282/s 6% -- -13% uccmp 325/s 22% 15% --` [download] Ah well.	[reply] [d/l] [select]
Re^4: Upper case and chomp by ikegami (Patriarch) on Feb 10, 2011 at 19:02 UTC
Re: Upper case and chomp by TechFly (Scribe) on Feb 09, 2011 at 21:09 UTC
Thanks guys. I did indeed forget that chomp() does not need to be assigned a new variable. I never thought much about using regex either. I am fairly new to that, so it does not come to mind right away. Thank you very much for the help.	[reply]