[Pompiuses]

I have this string:

$old_text = "ert, ert,ert,ert,ert";

Sometimes there is a space behind the comma, sometimes it's not. How can I test if there is a space behind a comma, and if it is'nt put a space behind it?

So that $old_text prints:
ert, ert, ert, ert, ert

Something like this:

Search through the string $old_text, and test
if(there is space behind a comma)
{do nothing}
else
{insert a space behind the comma}