86
DEVELOPING
COLDFUSION 9 APPLICATIONS
The CFML Programming Language
Las
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upda
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d 8/5/2010
<cfset i="CP">
<cfset "#i#"=["Charlie","Parker"]>
Creating complex multidimensional arrays
ColdFusion supports dynamic multidimensional arrays. When you declare an array with the
ArrayNew
function, you
specify the number of dimensions. You can create an asymmetrical array or increase the number of dimensions by
nesting arrays as array elements.
It is important to know that when you assign one array (array1) to an element of another array (array2), array1 is
copied into array2. The original copy of array1 still exists, independent of array2. You can then change the contents of
the two arrays independently.
The best way to understand an asymmetrical array is by looking at it. The following example creates an asymmetric,
multidimensional, array, and the
cfdump
tag displays the resulting array structure. Several array elements do not yet
contain data.
<cfset myarray=ArrayNew(1)>
<cfset myotherarray=ArrayNew(2)>
<cfset biggerarray=ArrayNew(3)>
<cfset biggerarray[1][1][1]=myarray>
<cfset biggerarray[1][1][1][10]=3>
<cfset biggerarray[2][1][1]=myotherarray>
<cfset biggerarray[2][1][1][4][2]="five deep">
<cfset biggestarray=ArrayNew(3)>
<cfset biggestarray[3][1][1]=biggerarray>
<cfset biggestarray[3][1][1][2][3][1]="This is complex">
<cfset myarray[3]="Can you see me">
<cfdump var=#biggestarray#><br>
<cfdump var=#myarray#>
Note:
The
cfdump
tag displays the entire contents of an array. It is an excellent tool for debugging arrays and array-
handling code.
Reviewing the code
The following table describes the code:
Code
Description
<cfset myarray=ArrayNew(1)>
<cfset myotherarray=ArrayNew(2)>
<cfset biggerarray=ArrayNew(3)>
Create three empty arrays, a 1D array, a 2D array, and a 3D array.
<cfset biggerarray[1][1][1]=myarray>
<cfset biggerarray[1][1][1][10]=3>
Make element [1][1][1] of the 3D
biggerarray
array be a copy
of the 1D array. Assign 3 to the [1][1][1][10] element of the
resulting array.
The biggerarray array is now asymmetric. For example, it does
not have a [1][1][2][1] element.
<cfset biggerarray[2][1][1]=myotherarray>
<cfset biggerarray[2][1][1][4][2]="five deep">
Make element [2][1][1] of the 3D array be the 2D array, and
assign the [2][1][1][4][2] element the value
"five deep"
.
The biggerarray array is now even more asymmetric.