Replace consecutive whitespaces with single whitespace

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Replace consecutive whitespaces with single whitespace by tilly (Archbishop) on Mar 26, 2009 at 05:56 UTC
Your replacement needs to be a space. \s is not a way to write that. `$str ="Any help would be greatly appreciated"; $str =~ s/\s+/ /g; print $str;` [download]	[reply] [d/l]
Re^2: Replace consecutive whitespaces with single whitespace by JavaFan (Canon) on Mar 26, 2009 at 12:47 UTC
To avoid Perl doing work when it doesn't have to, I prefer to write that as: `$str =~ s/\s{2,}/ /g;` [download] Note also that using `\s` matches more than the space the OP mentioned. In particular, `s/\s+/ /g` or `s/\s{2,}/ /g` will replace one (two) or more newlines with a space.	[reply] [d/l] [select]
Re^3: Replace consecutive whitespaces with single whitespace by tilly (Archbishop) on Mar 26, 2009 at 21:38 UTC
As for the newline issue, I thought of that, and then I thought that the OP quite possibly had data with tabs in it rather than multiple spaces. In that case you would want to match more than just spaces. You would also want to replace a single tab with a single space. Besides which, the extra work is negligible - if you care about that small of an efficiency then Perl is probably the wrong language to use in the first place.	[reply]
Re^4: Replace consecutive whitespaces with single whitespace by JavaFan (Canon) on Mar 27, 2009 at 08:10 UTC
Re^5: Replace consecutive whitespaces with single whitespace by tilly (Archbishop) on Mar 27, 2009 at 13:20 UTC
Re: Replace consecutive whitespaces with single whitespace by jwkrahn (Abbot) on Mar 26, 2009 at 06:23 UTC
Another way to do it: `$ perl -le' my $str = "Any help would be greatly appreciated"; $str =~ tr/ //s; print $str; ' Any help would be greatly appreciated` [download]	[reply] [d/l]
Re: Replace consecutive whitespaces with single whitespace by lakshmananindia (Chaplain) on Mar 26, 2009 at 05:56 UTC
Check with the following code `$str ="Any help would be greatly appreciated + "; $str =~ s/(\s)+/$1/g; print $str;` [download] --Lakshmanan G. Your Attempt May Fail, But Never Fail To Make An Attempt	[reply] [d/l]
Re: Replace consecutive whitespaces with single whitespace by Anonymous Monk on Mar 27, 2009 at 23:10 UTC
Performance summary of discussed options, based on Javafan's initial contribution, because I was interested: our $str = "x " x 1000; cmpthese -1, { single => sub { local $_ = $::str; s/\s+/ /g; }, multiple => sub { local $_ = $::str; s/\s{2,}/ /g; }, translate => sub { local $_ = $::str; tr/ //s; }, capture1 => sub { local $_ = $::str; s/(\s)+/$1/g; }, capture2 => sub { local $_ = $::str; s/(\s){2,}/$1/g; }, }; __END__ Rate capture1 single capture2 multiple translate capture1 1321/s -- -71% -82% -84% -99% single 4567/s 246% -- -37% -43% -97% capture2 7244/s 448% 59% -- -10% -95% multiple 8071/s 511% 77% 11% -- -95% translate 160627/s 12057% 3417% 2117% 1890% -- [download]	[reply] [d/l]