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DEVELOPING COLDFUSION 9 APPLICATIONS
The CFML Programming Language
About arrays
Traditionally, an array is a tabular structure used to hold data, much like a spreadsheet table with clearly defined limits
and dimensions.
In ColdFusion, you typically use arrays to temporarily store data. For example, if your site lets users order goods
online, you can store their shopping cart contents in an array. Using an array lets you make changes easily without
committing the information, which the user can change before completing the transaction, to a database.
Basic array concepts
Subsequent discussions of ColdFusion arrays are based on the following terms:
The relative complexity of the array structure.
Array dimension
The position of an element in a dimension, ordinarily surrounded by brackets: my1Darray[1],
Index
my2Darray[1][1], my3Darray[1][1][1].
Data stored at an array index.
Array element:
The simplest array is a one-dimensional array, like a row in a table. A one-dimensional array has a name (the variable
name) and a numeric index. The index number references a single entry, or cell, in the array.
Thus, the following statement sets the value of the fifth entry in the one-dimensional array MyArray to "Robert":
<cfset MyArray[5] = "Robert">
A basic two-dimensional (2D) array is like a simple table. A three-dimensional (3D) array is like a cube of data, and so
on. ColdFusion lets you directly create arrays with up to three dimensions. You can use multiple statements to create
arrays with more than three dimensions.
The syntax
is the same as saying "My2dArray is a two-dimensional array and the value of
my2darray[1][3]="Paul"
the array element index [1][3] is 'Paul'".
About ColdFusion arrays
ColdFusion arrays differ from traditional arrays, because they are dynamic. For example, in a conventional array, array
size is constant and symmetrical, whereas in a ColdFusion array, you can have rows of differing lengths based on the
data that is added or removed.
A conventional 2D array is like a fixed-size table made up of individual cells.
A ColdFusion 2D array is actually a one-dimensional array that contains a series of additional 1D arrays. Each of the
arrays that make up a row can expand and contract independently of any other column.
Last updated 8/5/2010
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