Question

i’m quite newbie about regex i’m trying to replace 2 or more commas to one and deleting the last comma.

    $string1=  preg_replace('(,,+)', ',', $string1);
    $string1= preg_replace('/,([^,]*)$/', '', $string1);

my quesiton is: Is there any way to do this with a single line of regex?

Answer 1

Yes, of course that’s possible:

$result = preg_replace(
    '/(?<=,)   # Assert that the previous character is a comma
    ,+         # then match one or more commas
    |          # or
    ,          # Match a comma
    (?=[^,]*$) # if nothing but non-commas follow till the end of the string
    /x', 
    '', $subject);