6.5 Functions for Vectors

Here are some functions that relate to vectors:

Function: vectorp object

This function returns t if object is a vector.

(vectorp [a])
     ⇒ t
(vectorp "asdf")
     ⇒ nil

Function: vector &rest objects

This function creates and returns a vector whose elements are the arguments, objects.

(vector 'foo 23 [bar baz] "rats")
     ⇒ [foo 23 [bar baz] "rats"]
(vector)
     ⇒ []

Function: make-vector length object

This function returns a new vector consisting of length elements, each initialized to object.

(setq sleepy (make-vector 9 'Z))
     ⇒ [Z Z Z Z Z Z Z Z Z]

Function: vconcat &rest sequences

This function returns a new vector containing all the elements of sequences. The arguments sequences may be true lists, vectors, strings or bool-vectors. If no sequences are given, the empty vector is returned.

The value is either the empty vector, or is a newly constructed nonempty vector that is not eq to any existing vector.

(setq a (vconcat '(A B C) '(D E F)))
     ⇒ [A B C D E F]
(eq a (vconcat a))
     ⇒ nil

(vconcat)
     ⇒ []
(vconcat [A B C] "aa" '(foo (6 7)))
     ⇒ [A B C 97 97 foo (6 7)]

The vconcat function also allows byte-code function objects as arguments. This is a special feature to make it easy to access the entire contents of a byte-code function object. See Byte-Code Objects.

For other concatenation functions, see mapconcat in Mapping Functions, concat in Creating Strings, and append in Building Lists.

The append function also provides a way to convert a vector into a list with the same elements:

(setq avector [1 two (quote (three)) "four" [five]])
     ⇒ [1 two (quote (three)) "four" [five]]
(append avector nil)
     ⇒ (1 two (quote (three)) "four" [five])