Regular expression for preg_replace

Can you help me please开发者_JAVA百科 what is the regular expression for this string change in preg_replace?

from "On the day, he is playing" to "he is good to play".

preg_replace("/On the day, he is playing/", "he is good to play", $input);

If you want to replace anything coming after the last comma "," in a string, try this:

preg_replace("/[^,]*$/", " he is good to play", $input, 1);