Re: How to introduce a frustrating bug with a single whitespace

The lesson? I probably should have used Text::Trim. :)

It could be, but I would say the lesson is to not try to do it all in one step. I remember reading a Randal Schwartz rant some time back about people continually trying to do whitespace trimming in one step, when it's much simpler and straight-forward to do it in two:

$user =~ s/^\s+//s;
$user =~ s/\s+$//s;
[download]

I think you'll find that that runs much faster than one regexp involving alternation....

Comment on Re: How to introduce a frustrating bug with a single whitespace Download Code

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Re^2: How to introduce a frustrating bug with a single whitespace by radiantmatrix (Parson) on Jan 17, 2008 at 21:16 UTC
I think you'll find that that runs much faster than one regexp involving alternation.... Well, I don't really care much about faster runtimes -- most of what I do waits on disk access and network I/O long before it runs into RAM or CPU limits, so which regex is fastest almost never comes into play. I try to write primarily for readability. I realize, of course, that "readability" is subjective. But, I find `s{^\s+\|\s+$}{}g` to be more readable than the two-line alternative. When I see that one line, I immediately think "ok, trim whitespace from the ends". When I see the two, I have to stop and think about it. Just me. One of the things I like about Python¹ is the readability of performing this action: `text = " a string of some sort, with space at either end " text = text.strip()` [download] I think that's what draws me to Text::Trim (if I have to do the step repeatedly, especially): `my $text = " a string of some sort, with space at either end "; $text = trim( $text );` [download] Of course, creating a dependency for something like that seems a little excessive, so I've recently taken to `my $TRIM_WHITESPACE_RE = qr/^\s+\|\s+$/ ## ... later on .. ## $text =~ s/$TRIME_WHITESPACE_RE//g;` [download] 1: I know, I know. :) Seriously, though, Python has some nifty things in it, even if I still like Perl better. <–radiant.matrix–> Ramblings and references The Code that can be seen is not the true Code I haven't found a problem yet that can't be solved by a well-placed trebuchet	[reply] [d/l] [select]

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Re^2: How to introduce a frustrating bug with a single whitespace
by radiantmatrix (Parson) on Jan 17, 2008 at 21:16 UTC

I think you'll find that that runs much faster than one regexp involving alternation....

Well, I don't really care much about faster runtimes -- most of what I do waits on disk access and network I/O long before it runs into RAM or CPU limits, so which regex is fastest almost never comes into play.

I try to write primarily for readability. I realize, of course, that "readability" is subjective. But, I find s{^\s+|\s+$}{}g to be more readable than the two-line alternative. When I see that one line, I immediately think "ok, trim whitespace from the ends". When I see the two, I have to stop and think about it. Just me.

One of the things I like about Python¹ is the readability of performing this action:

text = " a string of some sort, with space at either end   "
text = text.strip()
[download]

I think that's what draws me to Text::Trim (if I have to do the step repeatedly, especially):

my $text = " a string of some sort, with space at either end   ";
$text = trim( $text );
[download]

Of course, creating a dependency for something like that seems a little excessive, so I've recently taken to

my $TRIM_WHITESPACE_RE = qr/^\s+|\s+$/
## ... later on .. ##
$text =~ s/$TRIME_WHITESPACE_RE//g;
[download]

1: I know, I know. :) Seriously, though, Python has some nifty things in it, even if I still like Perl better.

<–radiant.matrix–>
Ramblings and references
The Code that can be seen is not the true Code
I haven't found a problem yet that can't be solved by a well-placed trebuchet

[reply]
[d/l]
[select]