删除彼此相邻的重复字符

Question

im trying to remove duplicate characters that are directly next to each other

1,2,3,4,5 - has a few commas but they are not to be removed 1,,2,,3,,4,,5 - would have to be turned into the regular 1,2,3,4,5 no matter how many commas are inbetween each number i would like to have just one. i have something similar which makes sure there are no commas at the end of the string:

$n = "1,2,3,4,5";
for ($i=0;$i< strlen($n);$i++) {

    if (substr($n, -1) == ',') {
        $n = substr($n, 0, -1);
    }
}

would appreciate some help on this matter,

Thanks :)

Answer 1

Looks like you only want to do this with commas, so it's extremely easy to do with preg_replace:

$n = '1,2,,3,,,,,4,5';
$n = preg_replace('/,+/', ',', $n);     // $n == '1,2,3,4,5'

Also you can replace the code you gave above that makes sure there are no commas at the end of a string with rtrim. It will be faster and easier to read:

$n = '1,2,3,4,5,,,,,'
rtrim($n, ',');                         // $n == '1,2,3,4,5'

You can combine them both into a one-liner:

$n = preg_replace('/,+/', ',', rtrim($n, ','));