13.2.11 digit-char-p [Function]

digit-char-p char &optional radix ⇒ weight

Arguments and Values::

char—a character.

radix—a radix. The default is 10.

weight—either a non-negative integer less than radix, or false.

Description::

Tests whether char is a digit in the specified radix (i.e., with a weight less than radix). If it is a digit in that radix, its weight is returned as an integer; otherwise nil is returned.

Examples::

 (digit-char-p #\5)    ⇒  5
 (digit-char-p #\5 2)  ⇒  false
 (digit-char-p #\A)    ⇒  false
 (digit-char-p #\a)    ⇒  false
 (digit-char-p #\A 11) ⇒  10
 (digit-char-p #\a 11) ⇒  10
 (mapcar #'(lambda (radix) 
             (map 'list #'(lambda (x) (digit-char-p x radix)) 
                  "059AaFGZ"))
         '(2 8 10 16 36))
 ⇒  ((0 NIL NIL NIL NIL NIL NIL NIL)
     (0 5 NIL NIL NIL NIL NIL NIL)
     (0 5 9 NIL NIL NIL NIL NIL)
     (0 5 9 10 10 15 NIL NIL)
     (0 5 9 10 10 15 16 35))

Affected By::

None. (In particular, the results of this predicate are independent of any special syntax which might have been enabled in the current readtable.)

See Also::

alphanumericp

Notes::

Digits are graphic characters.