• → LetterQ

DigitQ

WMA link

DigitQ[string]

yields True if all the characters in the string are digits, and yields False otherwise.

• • DigitQ["9"]

• • DigitQ["a"]

• • DigitQ["01001101011000010111010001101000011010010110001101110011"]

• • DigitQ["-123456789"]