替换用逗号分隔的字符串

Is there any way to change or convert a strings/int that are separated with commas?

Example :

$str = "121,232,343,454";

should result into :

str1, str1, str1, str1

Depending on the language you are using, this is often the split($str, ',') or split(',', $str) or $str.split(',') function

split() is deprecated !!! Please use explode($seperator, $string) instead.

$str = "a,b,c";
$items = explode(',', $str);