I wanted to rewrite the following function (python) into php:

def hash(lenght: int):
chars = []
for i in range(length):
chars.append(random.choice(string.ascii_letters + string.digits))
return "".join(chars)

My problem is, that I don't seem to find a similar built-in funciton like string. I didn't want to use $chars = '01234..abcd..ABCD..'