Alphabetic equivalent of PHP is_numeric

I am looking for a function that would be the alphabetic equivalent of is_numeric开发者_如何学编程. It would return true if there are only letters in the string and false otherwise. Does a built in function exist in PHP?

You want ctype_alpha()

If you're strictly looking for the opposite of is_numeric(), wouldn't !is_numeric() do the job for you? Or am I misunderstanding the question?

I would have used preg_match. But that's because I'd never heard of ctype_alpha().

if(!preg_match("/[^a-zA-Z]/", $teststring)) {
    echo "There are only letters in this string";
} else {
    echo "There are non-letters in this string";
}

!is_numeric((float)$variableToBeChecked); also preg_match('#^[a-z]+$#i',$variableToBeChecked); // for one or more letter character