Replace repeated characters regular expression

Question

I am newbie in regular expression.

I want to replace repeated characters from my string. here some example

$str1 = "aaa bbb cc dddd";  // output : a b c d

$str2 = "Google is the best";  // output : Google is the best

I found lots of question related this question on stackoverflow. But it does not satisfy my requirement.

I tried this (\w)\1 but this is not my solution

Any idea ? Thanks in advance

Edit :

More examples

 $str1 = "this is tesaaat. are you ook?";  // output : this is tesaaat. are you ook?

 $str2 = "Good morning mmmm yyyy friendssss ";  // output : Good morning m y friends

 $str3 = "Hello friendd okk";  // output : Hello friend okk 

Inshort I want to replace repeted charactor followed by space only.

Answer 1

You can use the following regex: \b(\w)\1+\b.

Explanation:

• A word break (\b)
• A single character
• The repetition (at least one time the same character)
• Again, a word break

EDIT: With more details, I would say you can get rid of the first \b. So, it becomes: (\w)\1+\b

Answer 2

Following regex would work for all letters in any language with u-unicode flag:

/([\p{L}\W])\1+(?= )/u

Explanations:

(                 # beginning of 1st capturing group
    [             # beginning of characters class
        \p{L}     # any letter from any language
        \W        # any non-word character
    ]             # end of character class
)                 # end of 1st capturing group
\1                # back reference to our 1st capturing group for repetition
+                 # one or more character repetition
(?= )             # using positive lookahead to be sure it's followed by a space

Using preg_replace to achieve the job:

$string = preg_replace("/([\p{L}\W])\1+(?= )/u", "$1", $string);

Output for your examples:

"aaa bbb cc dddd "  =>  "a b c d "
"Google is the best"  =>  "Google is the best"
"this is tesaaat. are you ook?"  =>  "this is tesaaat. are you ook?"
"Good morning mmmm yyyy friendssss "  =>  "Good morning m y friends "
"Hello friendd okk"  =>  "Hello friend okk"

Live demo