Functions that Operate on Arrays
================================
In this section, we describe the functions that accept all types of
arrays.
- Function: arrayp object
This function returns `t' if OBJECT is an array (i.e., a vector, a
string, a bool-vector or a char-table).
(arrayp [a])
=> t
(arrayp "asdf")
=> t
(arrayp (syntax-table)) ;; A char-table.
=> t
- Function: aref array index
This function returns the INDEXth element of ARRAY. The first
element is at index zero.
(setq primes [2 3 5 7 11 13])
=> [2 3 5 7 11 13]
(aref primes 4)
=> 11
(aref "abcdefg" 1)
=> 98 ; `b' is ASCII code 98.
See also the function `elt', in Note:Sequence Functions.
- Function: aset array index object
This function sets the INDEXth element of ARRAY to be OBJECT. It
returns OBJECT.
(setq w [foo bar baz])
=> [foo bar baz]
(aset w 0 'fu)
=> fu
w
=> [fu bar baz]
(setq x "asdfasfd")
=> "asdfasfd"
(aset x 3 ?Z)
=> 90
x
=> "asdZasfd"
If ARRAY is a string and OBJECT is not a character, a
`wrong-type-argument' error results. The function converts a
unibyte string to multibyte if necessary to insert a character.
- Function: fillarray array object
This function fills the array ARRAY with OBJECT, so that each
element of ARRAY is OBJECT. It returns ARRAY.
(setq a [a b c d e f g])
=> [a b c d e f g]
(fillarray a 0)
=> [0 0 0 0 0 0 0]
a
=> [0 0 0 0 0 0 0]
(setq s "When in the course")
=> "When in the course"
(fillarray s ?-)
=> "------------------"
If ARRAY is a string and OBJECT is not a character, a
`wrong-type-argument' error results.
The general sequence functions `copy-sequence' and `length' are
often useful for objects known to be arrays. Note:Sequence
Functions.