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Function `digit-char-p`

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 13.2.0 20(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))

In the above, recall that \EV's arrow takes up about two column positions, rather than three characters "\EV" -- so the grinding looks funny here in the source, but better on paper.

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.)

Exceptional Situations:

None.

Notes:

13.2.0 19Digits are graphic characters.