An array is a collection of pieces
of data all of the same type (typically, but the compiler doesn't check for
that) that are accessible by a numeric index. For example, the strings "cse",
"eee", and "ece" might all be stored in an array named btech_courses,
and if stored in that order, the first element would be accessible as btech_courses[0]
(the indexing always starts with 0) and the last would be btech_courses[2].
var
btech_courses:Array = ["cse", "eee", "ece"];
trace('the
first element is ' + btech_courses[0] + ' and the last element is ' + btech_courses[2]);
Pasting that code into a Flash movie
and ruuning it produces this in the Output panel: the first element is cse and the last element is ece. Like the String class, the Array
class has several methods that are indispensable for manipulating arrays.
Here's an example sequence of array statements, with the output from each:
|
Operation
|
Result
of trace statement
|
|
Create a 3-element array of information sources:
var sources:Array;
sources = new
Array("google","about","altavista");
trace("sources has " + sources.length + "
elements");
or, the abbreviated way (note the
square brackets):
var sources:Array = ["google",
"about", "altavista"];
|
sources has 3 elements
|
|
Use push method to add
another element at the end of the array
sources.push("metacrawler");
trace(sources);
|
google,about,altavista,metacrawler
(Note that running a trace on an array causes all elements to be dumped out as strings, one at a time, separated by commas) |
|
Use reverse method to
reverse order of array
sources.reverse();
trace("first element is now " + sources[0]);
|
first element is now metacrawler
|
|
pop the array to remove the last element
sources.pop();
trace(sources);
|
metacrawler,altavista,about
|
|
Use splice to insert
elements in the middle of the array
sources.splice(2, 0, "atomz",
"lycos");
trace(sources);
|
metacrawler,altavista,atomz,lycos,about
The 2 specifies that splicing will begin at the third element of the array; the 0 specifies that no elements are to be deleted (since splicing can be used either for adding elements to or deleting elements from an array); the last two parameters are array elements to insert into the array. |
|
Use splice to delete an
element in the array
sources.splice(3, 1);
trace(sources);
|
metacrawler,altavista,atomz,about
The 3 specifies that splicing will begin at the third element of the array; the 1 specifies that one element is to be deleted. |
|
Use unshift to add elements
to the beginning of the array
sources.unshift("dogpile");
trace(sources);
|
dogpile,metacrawler,altavista,atomz,about
|
|
sort the array alphabetically
sources.sort();
trace(sources);
|
about,altavista,atomz,dogpile,metacrawler
|
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