• elt sequence index → object
• (setf (elt sequence index) new-object)

• sequence - a proper sequence.
• index - a valid sequence index for sequence.
• object - an object.
• new-object - an object.

Accesses the element of sequence specified by index.

(defparameter *str* (copy-seq "0123456789")) 

→

*STR*



(elt *str* 6) 

→

#\6 



(setf (elt *str* 0) #\#) 

→

#\# 



*str* 

→

"#123456789" 

None.

None.

Should be prepared to signal an error of type type-error if sequence is not a proper sequence. Should signal an error of type type-error if index is not a valid sequence index for sequence.

• Function AREF
• Function NTH
• {\secref\ConstantModification}

aref may be used to access vector elements that are beyond the vector's fill pointer.

\issue{CONSTANT-MODIFICATION:DISALLOW}