regex - php Replacing multiple spaces with a single space

Question

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Answer 1

Use preg_replace() and instead of [ ] use s:

$output = preg_replace('!s+!', ' ', $input);

From Regular Expression Basic Syntax Reference:

d, w and s

Shorthand character classes matching digits, word characters (letters, digits, and underscores), and whitespace (spaces, tabs, and line breaks). Can be used inside and outside character classes.