Question

Just a Simple Quick Question.
I want to replace the Double Spaces at the begenning of the line by Tabs.
Currently I am trying with preg_replace('~^( {2})~', "\t", $text) but that replaces only the first occurrence of Double Space.

–EDIT–

preg_replace('~PATTERN~', "REPLACEMENT", "      HalloWorld")
//Should be equal to "\t\t\tHallo World"

Answer 1

You can use \G escape sequence for that:

$var = '    Hello    World'; //x4 spaces
echo preg_replace("/\G {2}/","\t",$var);

\G marks the location of the end of the previous match (or the beginning of the string for the first match); that way, all matches after the first one try to consume additional two spaces from the character previous match left off.