3.6 Combining Arrays
NN 4, IE 4
want to blend two or more separate arrays into one larger array.
To join arrays together, use the concat(
method of the array object, passing a reference to the other array as
var comboArray = myArray.concat(anotherArray);
Arrays joined through the concat( ) method are not
altered. Instead, the concat( ) method returns the
combined array as a new value, which you can preserve in a separate
variable. The base array (the one used to invoke the concat(
) method) comes first in the combined array.
For combining multiple arrays, pass the additional arrays as
comma-delimited parameters to the concat( )
var comboArray = myArray.concat(otherArray1, otherArray2, otherArray3);
The combined array has items in the same order as they appear in the
The concat( ) method is not limited to tacking one
array onto another. Comma-delimited parameters to the method can be
any data type. A value of any data type other than an array becomes
another entry in the main array—in the same sequence as the
parameters. You can even combine arrays and other data types in the
group of parameters passed to the method.
In addition to the concat( ) method, a quartet of
array methods let you treat an array like a stack for tacking on and
removing items from the front or backends of the array. The
push( ) method lets you append one or more items
to the end of an array; the corresponding pop(
method removes the last item from the array and returns its value.
You can perform the same operations at the beginning of the array
with the unshift( ) (append) and shift( )
(remove) methods. All four of these methods are implemented in NN 4
or later and IE 5.5 or later for Windows.
3.6.4 See Also
Recipe 3.5 for sorting an array—something you may wish to do
once you add to an array; Recipe 3.7 for dividing an array.