a method of selecting random characters from given string

Question

Can anyone help me with a solution that pulls the position and value of a random character from a given string using PHP. For example I have a a string variable $string = \

Answer 1

1. find the length of the string , ($length)
2. use random function to generate random value within that range , ($a=Random.get($length))
3. use substring function to get the value of the random position.($string.substring($a,1))

sorry i dont know syntax for php (java \m/)