Find & Replace

mantra2006 has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Find & Replace by davorg (Chancellor) on Aug 10, 2006 at 14:51 UTC
`perl -i~ -pe 's/,+/,/g' your_filename_goes_here` [download] -- <http://dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re^2: Find & Replace by mantra2006 (Hermit) on Aug 10, 2006 at 15:05 UTC
Hello This command worked..is there any way to specify the line numbers so that only first line and last line of the file will be replaced Thanks & Regards Sridhar	[reply]
Re^3: Find & Replace by sh1tn (Priest) on Aug 10, 2006 at 16:08 UTC
`perl -i -pe '(1==$. or eof) && s/,,+/,/' file_name` [download]	[reply] [d/l]
Re: Find & Replace by McDarren (Abbot) on Aug 10, 2006 at 14:50 UTC
So for each line in your file, you want to replace one or more commas at the end of the line, with a single comma - yes? If that's the case, it's as simple as: `while (<LINES>) { $_ =~ s/,+$/,/; }` [download] (You could actually do this from the command line with something like: `perl -pi -e 's/,+$/,/' file.txt`)	[reply] [d/l] [select]
A reply falls below the community's threshold of quality. You may see it by logging in.
Re: Find & Replace by prasadbabu (Prior) on Aug 10, 2006 at 14:52 UTC
Sridhar, Here is one way to do it. `use strict; use warnings; my $string = 'Hello,World,23,,,, test,test,test test,test,test test,test,test test,test,test end,bye,,,,'; $string =~ s/((?:first line last word\|last line last word),)[^\n]/$1/ +g; #in your file $string =~ s/((?:23\|bye),)[^\n]/$1/g; #here in this string print $string;` [download] update:Oops! Already two answers above me. Better solutions from davorg++ and McDarren++ Prasad	[reply] [d/l]
Re^2: Find & Replace by mantra2006 (Hermit) on Aug 10, 2006 at 14:58 UTC
Hello Thanks for the replies. The content will be in file and I need to replace commas in first and last line only... Thanks & Regards Sridhar	[reply]
Re^3: Find & Replace by McDarren (Abbot) on Aug 10, 2006 at 15:08 UTC
Well, if the file is not too big, a simple (but slightly convoluted) way to do that would be to read all the lines into an array, edit the first and last elements of the array, and then write the file back out again. Like so: `open IN, "<", "file.txt" or die "Cannot open file.txt for reading:$!\n +"; my @lines = <IN>; $lines[0] =~ s/,+$/,/; $lines[-1] =~ s/,+$/,/; open OUT, ">", "file.txt" or die "Cannot open file.txt for writing:$!\ +n"; print OUT for @lines; close OUT;` [download]	[reply] [d/l]
Re^4: Find & Replace by mantra2006 (Hermit) on Aug 10, 2006 at 15:19 UTC
Re^4: Find & Replace by mantra2006 (Hermit) on Aug 10, 2006 at 17:45 UTC
Re^4: Find & Replace by mantra2006 (Hermit) on Aug 10, 2006 at 17:20 UTC
Re: Find & Replace by ercparker (Hermit) on Aug 10, 2006 at 18:59 UTC
you can also try this: `while (<DATA>) { s{(?:(?<=23,)\|(?<=bye,)),+}{}; print; } __DATA__ Hello,World,23,,,, test,test,test test,test,test test,test,test test,test,test end,bye,,,,` [download]	[reply] [d/l]
Re^2: Find & Replace by johngg (Canon) on Aug 10, 2006 at 20:41 UTC
Moving the `,+` outside of the alternation also works. `while (<DATA>) { s{(?:(?<=23,)\|(?<=bye,)),+}{}; print; }` [download] Cheers, JohnGG	[reply] [d/l] [select]