http://www.perlmonks.org?node_id=782138

Good point. I've tried the 3 methods below:
```if (\$x =~ /\s/)
and
```if (substr(\$x, -1) =~ /^\s/
and
```if (rindex(\$x," ") == 0 || rindex(\$x,"\r") == 0 ||  rindex(\$x,"\n") ==
+ 0 ||  rindex(\$x,"\t") == 0)
The rindex method is much faster on the data that has spaces; otherwise the substr method is the fastest. Any other good ideas, keeping in mind that the data (I think) won't often contain any trailing spaces?

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Re^5: How do I quickly strip blank space from the beginning/end of a string?
by ikegami (Pope) on Jul 22, 2009 at 04:22 UTC

\$x =~ /\s/
doesn't work. It should be
\$x =~ /\s\z/
Bonus: The speed of fixed version won't depend on the length of the string like the broken one did.

if (rindex(\$x," ") == 0 || rindex(\$x,"\r") == 0 || rindex(\$x,"\n") == 0 || rindex(\$x,"\t") == 0)
doesn't work. It should be
if (rindex(\$x," ") == length(\$x)-1 || rindex(\$x,"\n") == length(\$x)-1 || rindex(\$x,"\t") == length(\$x)-1 || rindex(\$x,"\r") == length(\$x)-1)
Or just
my \$ch = substr(\$x, -1); \$ch eq " " || \$ch eq "\n" || \$ch eq "\t" || \$ch eq "\r"

And then there's
length(\$x) && index(" \n\t\r", substr(\$x, -1)) >= 0

You should be concentrating on writing code that actually works before worrying about operations that take 0.00001 second.