Re: Splitting on tabs then removing extra white space with map

Since nobody mentioned it, the problem is that the return value of s/// isn't the modified string.

my @points = map { s/\s+//; $_ } split(/\t/, $_);
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But then you're modifying map's arguments without intending to do so. Modifying $_ in map is a bad idea. (If you really do mean to modify map's arguments, using for would make your intent more obvious.)

my @points = map { local $_ = $_; s/\s+//; $_ } split(/\t/, $_);
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Yuck! List::MoreUtils provides a function for just this purpose. It even uses a better method of localizing $_.

use List::MoreUtils qw( apply );
my @points = apply { s/\s+// } split(/\t/, $_);
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Re^2: Splitting on tabs then removing extra white space with map by c4onastick (Friar) on Sep 18, 2007 at 06:01 UTC
Ah! Thank you! That makes much more sense. I tried every context permutation between map and split I could think of. Modifying $_ in map is a bad idea. I though this was one of map's strengths? Am I mistaken?	[reply]
Re^3: Splitting on tabs then removing extra white space with map by ikegami (Patriarch) on Sep 18, 2007 at 12:50 UTC
In what situation would it be a strength? `map` is usually used as `my @new = map { ... } @old;` [download] By changing `$_`, you also change `@old` in non-obvious manner.	[reply] [d/l] [select]