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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, an empty vector is returned.

The value is a newly constructed 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])