digit-char-p

ToC

Allegro CL

ANSI Common Lisp

13 Characters

13.2 Dictionary of Characters

13.2.11 digit-char-p

Function

Syntax:

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.

Allegro CL Implementation Details:

None.