ctype_digit()

ctype_digit() — Check for numeric character(s).

ctype_digit() — Checks if all of the characters in the provided string, text, are numerical.

Inputs: text: The tested string. If an int between -128 and 255 inclusive is provided, it is interpreted as the ASCII value of a single character (negative values have 256 added in order to allow characters in the Extended ASCII range). Any other integer is interpreted as a string containing the decimal digits of the integer.

Returns: Returns true if every character in the string text is a decimal digit, false otherwise. When called with an empty string the result will always be false.