regex to check the string contains only letter and numbers but not only numbers

Question

I need a help with regex which checks the string contains only letter and numbers but not only numbers

Valid

* letters
* 1wret
* 0123chars
* chars0123
*          


        

Answer 1

^(?=.*[a-z])[a-zA-Z0-9]+$

• (?=.*[a-z]) positive lookahead to make sure that there is at least one letter in the string (but doesn't consume any characters - gives up the matched characters as soon as it returns (in this case, as soon as it finds a letter)).
• [a-zA-Z0-9]+ make sure string contains only alphanumeric characters.
• ^ and $ are start and end of string delimiters.