CLHS: Accessor ELT

#

Accessor ELT

Syntax:

elt sequence index => object

`(setf (`elt sequence index`)` new-object`)`

Arguments and Values:

sequence---a proper sequence.

index---a valid sequence index for sequence.

object---an object.

new-object---an object.

Description:

Accesses the element of sequence specified by index.

Examples:

     (setq str (copy-seq "0123456789")) =>  "0123456789"
     (elt str 6) =>  #\6
     (setf (elt str 0) #\#) =>  #\#
     str =>  "#123456789"

Side Effects: None.

Affected By: None.

Exceptional Situations:

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.

See Also:

aref, nth, Section 3.2.1 (Compiler Terminology)

Notes:

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

The following X3J13 cleanup issue, not part of the specification, applies to this section:

- CONSTANT-MODIFICATION:DISALLOW

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