将所有重复出现的字符串替换为单个字符串

Question

How replace all repeated occurrences of string for the single same:

I have string like:

1-string-2-string-3-string-55-otherstring-66-otherstring

I need replace for:

1-2-3-string-55-66-otherstring

How can I do that?

Answer 1

You could do this:

$str = '1-string-2-string-3-string-55-otherstring-66-otherstring';
print_r(implode('-', array_reverse(array_unique(array_reverse(explode('-', $str))))));

Live demo

Or using Regular Expressions:

(\w++)-?(?=.*\b\1\b)

Breakdown:

• (\w++) Match and capture a word
• -? Match following hyphen if any
• (?= Start of positive lookahead
  • .*\b\1\b Recent captured word should repeat
• ) End of lookahead

Live demo

PHP code:

echo preg_replace('~(\w++)-?(?=.*\b\1\b)~', '', $str);