preg_replace all spaces

Question

I'm trying to replace all spaces with underscores and the following is not working:

$id = "aa aa"; echo $id; preg_replace('/\s+/', '_', $id); echo $id; 

prints

aa aaaa aa 

Answer 1

The function preg_replace doesn't modify the string in-place. It returns a new string with the result of the replacement. You should assign the result of the call back to the $id variable:

$id = preg_replace('/\s+/', '_', $id); 

Answer 2

I think str_replace() might be more appropriate here:

$id = "aa aa"; $id = str_replace(' ', '_', $id); echo $id;