Re: How do I remove whitespace at the beginning or end of my string?

[Mago]

Remove whitespace at the beginning and end of your string, as well as consecutive whitespace (more than one whitespace character in a row) throughout the string.

$string = join(' ',split(' ',$string));

[Abigail-II]

Beside removing whitespace at the beginning and end of the string, the above line will also remove any consecutive white space in the string.

Abigail

[roju]

If you want to preserve internal whitespace, try

s/         #replace
^[\s]*     #the start of the string followed by any number of spaces
(.*)       #zero or more characters of anything, stuff into $1.  This 
+is the actual string we want.
(?<!\s)    #look-behind assertion to get to the last non-whitespace ch
+ar
\s*$       #match whitespace until EOL
/$1/x;     #replace with the (.*)

Update: If you value your CPU time, use one of the other regular expressions instead. I got caught up in using the .*, leading to the need for the look-behind assertion. Better answers can be found here. For the interested,

Benchmark: timing 100000 iterations of my_long_one, one_liner, two_lin
+er...
my_long_one:  6 wallclock secs ( 4.62 usr +  0.00 sys =  4.62 CPU) @ 2
+1659.09/s (n=100000)
one_liner:  3 wallclock secs ( 3.89 usr +  0.00 sys =  3.89 CPU) @ 256
+73.94/s (n=100000)
two_liner:  1 wallclock secs ( 2.16 usr +  0.00 sys =  2.16 CPU) @ 462
+10.72/s (n=100000)

Using
my_long_one => s/^[\s]*(.*)(?<!\s)\s*$/$1/
one_liner => s/^\s+|\s+$//g
two_liner => s/^\s+//g; s/s+$//g