Question

In java, which regular expression can be used to replace these, for example:

before: aaabbb after: ab

before: 14442345 after: 142345

thanks!

Answer 1

In perl

s/(.)\1+/$1/g; 

Does the trick, I assume if java has perl compatible regexps it should work too.

Edit: Here is what it means

s {     (.)  # match any charater ( and capture it )     \1   # if it is followed by itself      +    # One or more times }{$1}gx;  # And replace the whole things by the first captured character (with g modifier to replace all occurences) 

Edit: As others have pointed out, the syntax in Java would become

original.replaceAll('(.)\\1+', '$1'); 

remember to escape the \1