Replace repeated letters using Regular expression in JAVA

Question

Suppose I have a string like :

      String s = "hellllooooo howwwwwww areeeeeee youuuuuuu";

I want to discard the repeated letters and want to get :

     "helloo howw aree youu"

I have done the matching using ::

        matches(".*([a-z])\\1{3,}.*"

But how can I replace the helloooooooo to helloo and the others ?

If I may ask: I haven't seen "\\1" in a regexp pattern before, what does it do? — Timothée Groleau
– Timothée Groleau, Commented Mar 5, 2013 at 0:54

jdb · Accepted Answer · 2013-03-05 00:59:49Z

4

Any of the following produces the result you want:

s = s.replaceAll("([a-z])\\1+", "$1$1");

s = s.replaceAll("(([a-z])\\2)\\2*", "$1");

answered Mar 5, 2013 at 0:59

jdb

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