Adobe 38043740 Developing Applications - Page 89

DEVELOPING COLDFUSION 9 APPLICATIONS 84 The CFML Programming Language The following figure represents a ColdFusion 2D array: a[1] a[2] a[3] a[4] a[1][1] a[1][2] a[1][3] a[1][4] a[2][1] a[2][5] a[3][1] a[3][2] a[4][1] a[4][3] A ColdFusion 3D array is essentially three nested sets of 1D arrays. The differences between traditional and ColdFusion 3D arrays are similar, but much harder to show on a page. Dynamic arrays expand to accept data that you add to them and contract as you remove data from them. Basic array techniques Referencing array elements You reference array elements by enclosing the index with brackets: arrayName[x] where x is the index that you want to reference. In ColdFusion, array indexes are counted starting with position 1, which means that position 1 in the firstname array is referenced as firstname[1]. For 2D arrays, you reference an index by specifying two coordinates: myarray[1][1]. You can use ColdFusion variables and expressions inside the brackets to reference an index, as the following example shows: Note: The IsDefined function does not test the existence of array elements. Instead, place any code that could try to access an undefined array element in a try block and use a catch block to handle exceptions that arise if elements do not exist. Creating arrays In ColdFusion, you can create arrays explicitly, by using a function to declare the array and then assigning it data, or implicitly by using an assignment statement. You can create simple or complex, multidimensional arrays. Last updated 1/20/2012