rplaca, rplacd

rplaca, rplacd Function

Syntax:

rplaca cons object → cons

rplacd cons object → cons

Pronunciation:

rplaca: [ r—e plak* ] or [ r* plak* ]

rplacd: [ r—e plakd* ] or [ r* plakd* ] or [ r—e plakd—e ] or [ r* plakd—e ]

Arguments and Values:

cons—a cons.

object—an object.

Description:

rplaca replaces the car of the cons with object.

rplacd replaces the cdr of the cons with object.

Examples:

(defparameter \*some-list\* (list\* ’one ’two ’three ’four)) → \*some-list\* 
\*some-list\* → (ONE TWO THREE . FOUR) 
(rplaca \*some-list\* ’uno) → (UNO TWO THREE . FOUR) 
\*some-list\* → (UNO TWO THREE . FOUR) 
(rplacd (last \*some-list\*) (list ’IV)) → (THREE IV) 
\*some-list\* → (UNO TWO THREE IV) 

Side Effects:

The cons is modified.

Should signal an error of type type-error if cons is not a cons.

car, cdr, caar, cadr, cdar, cddr, caaar, caadr, cadar, . . .

Expanded Reference: rplaca, rplacd

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