Re^4: How do I quickly strip blank space from the beginning/end of a string?


Problems? Is your data what you think it is?
	PerlMonks

Re^4: How do I quickly strip blank space from the beginning/end of a string?

by blahblahblah (Priest)

on Jul 22, 2009 at 01:12 UTC ( [id://782138]=note: print w/replies, xml )

Need Help??

in reply to Re^3: How do I quickly strip blank space from the beginning/end of a string?
in thread How do I quickly strip blank space from the beginning/end of a string?

Good point. I've tried the 3 methods below:

if ($x =~ /\s/)
[download]

and

if (substr($x, -1) =~ /^\s/
[download]

and

if (rindex($x," ") == 0 || rindex($x,"\r") == 0 ||  rindex($x,"\n") ==
+ 0 ||  rindex($x,"\t") == 0)
[download]

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?

Comment on Re^4: How do I quickly strip blank space from the beginning/end of a string? Select or Download Code

Replies are listed 'Best First'.

Re^5: How do I quickly strip blank space from the beginning/end of a string?
by ikegami (Patriarch) 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.

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom