Re: how to search and replace the match with specific number of times in a string

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Re^2: how to search and replace the match with specific number of times in a string by JavaFan (Canon) on Jan 29, 2010 at 11:09 UTC
Note that doesn't work in the general case. For instance, suppose you want to replace first three sequences of whitespace with a single space. `s/\s+/ / for 1 .. 3;` [download] would replace the first sequence three times.	[reply] [d/l]
Re^2: how to search and replace the match with specific number of times in a string by loki (Novice) on Jan 29, 2010 at 13:47 UTC
hi but am facing problem when am replacing by `$s="*abc"; $s=~s{\}{\\n} for 1..2; print$s;` [download] it replaces first by \n and the rest it ignores... why can any one explain me pls? `my output was: abc` [download] but desired was ` * ab**c` [download]	[reply] [d/l] [select]
Re^3: how to search and replace the match with specific number of times in a string by Verillion (Initiate) on Jan 29, 2010 at 17:30 UTC
I believe you can get the function to work expanding the regex a little bit. `$s = "*abc"; $s =~ s/\([^\n])/\\n\1/ for 1 .. 2; print $s;` [download] Output was: ` * ab*c` [download] Since you know the state it's going to be after it's changed, you can include that in the regex. Hence , not followed by \n will match, along with the for loop suggested earlier, gives you your count. Using \1 here just puts the next value (after the matched ) back into the string. Update:* markkawika's comment might be below threshold, so I'll add it here as well, since his regex is better than mine. Suggested regex: `s/\(?!\n)/\n/`	[reply] [d/l] [select]
Re^4: how to search and replace the match with specific number of times in a string by markkawika (Monk) on Jan 29, 2010 at 19:26 UTC
That's one way, but I think a negative look-ahead would serve you better in this specific case: `$s =~ s/\(?!\n)/\n/;` [download] Also, you don't need to escape the `*` in the replacement string.	[reply] [d/l] [select]
Re^3: how to search and replace the match with specific number of times in a string by Ratazong (Monsignor) on Jan 29, 2010 at 14:07 UTC
your code does 2 replaces: * will be replaced by \n => so your string is `\nab*c` again, the first will be replaced by \n, giving you `\n\nab*c` If you want to continue your approach, a solution could be: replace by some string not containing your search-pattern (e.g. X) `$s=~s{\}{X} for 1..2;` replace the new string by your search-pattern `$s=~s{X}{\\n} for 1..2;` Or follow some other advice given in this thread... HTH, Rata	[reply] [d/l] [select]