How to remove all repeating characters in a string in place

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

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Re: How to remove all repeating characters in a string in place by mr_ron (Deacon) on Jan 30, 2016 at 23:29 UTC
`s/(.)\g1+//g` [download] It's all pretty much in the Perl regex tutorial although a little background and experience with regexes may help. Ron	[reply] [d/l]
Re: How to remove all repeating characters in a string in place by Cristoforo (Curate) on Jan 30, 2016 at 23:33 UTC
This substitution will give the results you want. `$str =~ s/(.)\1+//g;` Update: Redid after seeing mr_ron's post. (was originally `s/((.)\2+)//g;`)	[reply] [d/l] [select]
Re^2: How to remove all repeating characters in a string in place by punitpawar (Sexton) on Jan 31, 2016 at 15:48 UTC
Thanks a lot for the help. Yes this works , I was trying to do s/(\w)$1+//; I forgot that $1 is not defined inside a pattern as it is being matched and hence I should be using \1 instead	[reply]
Re^3: How to remove all repeating characters in a string in place by AnomalousMonk (Archbishop) on Jan 31, 2016 at 19:19 UTC
... I was trying to do s/(\w)$1+//; ... Had you given this information in addition to the info you gave in the OP, it would have been most helpful in addressing your problem. Please always try to give some indication of what you have tried, how it failed, what you expected, etc. Please see How do I post a question effectively?. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l]
Re: How to remove all repeating characters in a string in place by GotToBTru (Prior) on Jan 30, 2016 at 22:49 UTC
What have you tried so far? There are many ways to do this, most of which are documented in any tutorial about regular expressions. Try Regular Expressions Tutorial, the Basics (for BEGINNERS). After a few paragraphs, there is the section entitled Substitution Operators, and that should tell you what you need to know. Update: the following section on character classes will also be useful, I think. But God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us. Romans 5:8 (NASB)	[reply]
Re: How to remove all repeating characters in a string in place by Discipulus (Canon) on Jan 30, 2016 at 22:50 UTC
Yes, alternance operator in regex `\|` and the global regex modifier `g` `perl -e "$ARGV[0]=~s/a\|b\|f//g;print $ARGV[0]" aaabbcdeffgh cdegh` [download] The `s///g` behaviour is introduced in perlrequick's Search and Replace part and in the Global Matching part of perlretut HtH L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l] [select]
Re: How to remove all repeating characters in a string in place by 2teez (Vicar) on Jan 30, 2016 at 23:26 UTC
Hi, `...or any other way to do this ?` What about using tr/// you can do `perldoc -f tr` on your CLI to read the documentation. The following works like you wanted: `perl -we "$ARGV[0]=~tr[abf]()ds; print $ARGV[0]" aaabbcdeffgh # prin +ts cdegh` [download] If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply] [d/l] [select]