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code-char

code-char Function

Syntax:

code-char code → char-p

Arguments and Values:

code—a character code.

char-p—a character or nil.

Description:

Returns a character with the code attribute given by code. If no such character exists and one cannot be created, nil is returned.

Examples:

(code-char 65.) → #\A ;in an implementation using ASCII codes 
(code-char (char-code #\Space)) → #\Space ;in any implementation

Affected By:

The implementation’s character encoding.

See Also:

char-code

Notes:

Expanded Reference: code-char​

Converting a code to a character​

code-char returns the character with the given character code, or NIL if no such character exists.

;; On ASCII-based implementations:
(code-char 65)
=> #\A
(code-char 97)
=> #\a
(code-char 48)
=> #\0
(code-char 32)
=> #\Space

Round-tripping with char-code​

code-char and char-code are inverse operations for valid character codes.

(code-char (char-code #\A))
=> #\A
(code-char (char-code #\Space))
=> #\Space
(char-code (code-char 65))
=> 65

Invalid codes return NIL​

If the code does not correspond to any character, code-char returns NIL rather than signaling an error.

;; Codes at or above char-code-limit are not valid character codes:
;; (code-char char-code-limit) would not be a valid call since
;; char-code-limit is not a character code

;; Negative numbers are not valid character codes and should not be passed

Building a character range​

You can use code-char with char-code to iterate over a range of characters.

(loop for code from (char-code #\A) to (char-code #\Z)
      collect (code-char code))
=> (#\A #\B #\C #\D #\E #\F #\G #\H #\I #\J #\K #\L #\M #\N #\O #\P #\Q #\R #\S #\T #\U #\V #\W #\X #\Y #\Z)

Generating a string from character codes​

(map 'string #'code-char '(72 101 108 108 111))
=> "Hello"