How to make these reg exp changes?

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

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Re: How to make these reg exp changes? by keszler (Priest) on Nov 15, 2009 at 22:52 UTC
Here's one method: `perl -e "$s='OOO....MMMM..IIIII';$s=~s/(.)(\.+)/$1.$1 x length($2)/eg; +print $s,$/;" # OOOOOOOMMMMMMIIIII` [download] Or more appropriately for here: `perl -e "$s='JJ..A....PPPP..HHHH...';$s=~s/(.)(\.+)/$1.$1 x length($2) +/eg;print $s,$/;" # JJJJAAAAAPPPPPPHHHHHHH` [download]	[reply] [d/l] [select]
Re: How to make these reg exp changes? by ikegami (Patriarch) on Nov 15, 2009 at 23:17 UTC
`s/(.)(\.+)/$1 x (1+length $2)/seg;` [download] For example, `$ perl -wle' $_ = "III...MMMMMOOOO....MMMIIIII"; print; s/(.)(\.+)/$1 x (1+length $2)/seg; print; ' III...MMMMMOOOO....MMMIIIII IIIIIIMMMMMOOOOOOOOMMMIIIII` [download] Update: Oops, this window must have been open a while. keszler already gave basically the same answer a while ago. As punishment, I'll give an alternative that might be faster for short strings: `$ perl -wle' $_ = "III...MMMMMOOOO....MMMIIIII"; print; 1 while s/(.)(\.)/$1$1/sg; print; ' III...MMMMMOOOO....MMMIIIII IIIIIIMMMMMOOOOOOOOMMMIIIII` [download]	[reply] [d/l] [select]
Re: How to make these reg exp changes? by Anonymous Monk on Nov 15, 2009 at 22:43 UTC
For the first substitution case, I tried: `if($string=~/(.*?)(\.+)(M+i+)/i) { $first=$1; $change=$2; $len_change=length($change); $third=$3; print $first; print 'O' x $len_change; print $third; print "\n"; }` [download] and it printed: `III...MMMMMOOOOOOOOMMMiiiii` [download] which is correct. Is there a quicker way however?	[reply] [d/l] [select]
Re^2: How to make these reg exp changes? by Anonymous Monk on Nov 15, 2009 at 22:51 UTC
But the thing is that although I change `...MMMiii` to `OOOMMMiii` , at the same time, I must change `III...MMMOOO` to `IIIMMMOOOO` which is not covered by the previous reg exp... any suggestions?	[reply] [d/l] [select]
Re: How to make these reg exp changes? by Anonymous Monk on Nov 15, 2009 at 23:26 UTC
Your solutions work OK - thanks to both of you! But I have a question (maybe I should have written this before): What I must change is: `....MMMMiiii => ooooMMMMiiii ....MMMMoooo => iiiiMMMMoooo iiiiMMMM.... => iiiiMMMMoooo ooooMMMM.... => ooooMMMMiiii` [download] I mean, If you do not have some character before the '.' , how will it understand to replace for example, '.' with 'I' if I have 'O' after the string of 'M'? Is there any chance that this can be done?	[reply] [d/l]
Re^2: How to make these reg exp changes? by ikegami (Patriarch) on Nov 15, 2009 at 23:39 UTC
`$ perl -wle' my %neg = ( o => "i", i => "o" ); while (<>) { chomp; s/([io])(M)(\.+)/ $1.$2.( $neg{$1} x length($3) ) /eg; s/(\.+)(?=M([io]))/ $neg{$2} x length($1) /eg; print; } ' ....MMMMiiii ....MMMMoooo iiiiMMMM.... ooooMMMM.... ooooMMMMiiii iiiiMMMMoooo iiiiMMMMoooo ooooMMMMiiii` [download] Simpler version that only works with Perl 5.10+: `$ perl -wle' my %neg = ( o => "i", i => "o" ); while (<>) { chomp; s/([io])M\K(\.+)/ $neg{$1} x length($2) /eg; s/(\.+)(?=M([io]))/ $neg{$2} x length($1) /eg; print; } ' ....MMMMiiii ....MMMMoooo iiiiMMMM.... ooooMMMM.... ooooMMMMiiii iiiiMMMMoooo iiiiMMMMoooo ooooMMMMiiii` [download] I could have used `-p` above, but I wanted to make clear that `%neg` only needs to be initialized once without complicating the issue by adding a `BEGIN`. Here's the 5.10+ version using `-p`: `perl -ple' BEGIN { %neg = qw( i o o i ) } s/([io])M\K(\.+)/ $neg{$1} x length($2) /eg; s/(\.+)(?=M([io]))/ $neg{$2} x length($1) /eg; '` [download] Update: Added \K version. \K rocks. Update: Added explanation about `-p`.	[reply] [d/l] [select]
Re^3: How to make these reg exp changes? by Anonymous Monk on Nov 16, 2009 at 00:09 UTC
exactly what I was looking for... The trick with the hash was just the thing! Thank you very much!	[reply]
Re^4: How to make these reg exp changes? by ikegami (Patriarch) on Nov 16, 2009 at 00:15 UTC
Re^4: How to make these reg exp changes? by Anonymous Monk on Nov 16, 2009 at 00:23 UTC
Re^5: How to make these reg exp changes? by ikegami (Patriarch) on Nov 16, 2009 at 01:28 UTC