ACTIONSCRIPT 3.0

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with arrays
The sortOn() method (Array class only)
The sortOn() method is designed for Array objects with elements that contain objects. These objects are expected to
have at least one common property that can be used as the sort key. The use of the sortOn() method for arrays of any
other type yields unexpected results.
Note: The Vector class does not include a sortOn() method. This method is only available for Array objects.
The following example revises the poets Array so that each element is an object instead of a string. Each object holds
both the poet’s last name and year of birth.
var poets:Array = new Array();
poets.push({name:"Angelou", born:"1928"});
poets.push({name:"Blake", born:"1757"});
poets.push({name:"cummings", born:"1894"});
poets.push({name:"Dante", born:"1265"});
poets.push({name:"Wang", born:"701"});
You can use the sortOn() method to sort the Array by the born property. The sortOn() method defines two
parameters, fieldName and options. The fieldName argument must be specified as a string. In the following
example, sortOn() is called with two arguments, "born" and Array.NUMERIC. The Array.NUMERIC argument is used
to ensure that the sort is done numerically instead of alphabetically. This is a good practice even when all the numbers
have the same number of digits because it ensures that the sort will continue to behave as expected if a number with
fewer or more digits is later added to the array.
poets.sortOn("born", Array.NUMERIC);
for (var i:int = 0; i < poets.length; ++i)
{
trace(poets[i].name, poets[i].born);
}
/* output:
Wang 701
Dante 1265
Blake 1757
cummings 1894
Angelou 1928
*/
Sorting without modifying the original array (Array class only)
Generally, the sort() and sortOn() methods modify an Array. If you wish to sort an Array without modifying the
existing array, pass the Array.RETURNINDEXEDARRAY constant as part of the options parameter. This option directs
the methods to return a new Array that reflects the sort and to leave the original Array unmodified. The Array returned
by the methods is a simple Array of index numbers that reflects the new sort order and does not contain any elements
from the original Array. For example, to sort the poets Array by birth year without modifying the Array, include the
Array.RETURNINDEXEDARRAY constant as part of the argument passed for the options parameter.
The following example stores the returned index information in an Array named indices and uses the indices array
in conjunction with the unmodified poets array to output the poets in order of birth year:
Last updated 4/22/2013
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