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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 ( #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 ($x =~ /\s/)
and
if (substr($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.

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