配列の生成
<![CDATA[
(1)
var myArray = new Array();
myArray[0] = "Alice";
myArray[1] = "Fred";
(2)
var myArray = new Array ("Alice", "Fred", "Jean");
(3)
var myArray = ["Alice", "Fred", "Jean"];
(応用)
lengthプロパティを使って、要素を追加する。
myArray[myArray.length] = "Steve";
]]>
多次元配列
<![CDATA[
(1)
var array1 = new Array(10,20,30,40);
var array2 = new Array(100,200,300,400);
var array3 = new Array(1000,2000,3000,4000);
var myArray = new Array(array1, array2, array3);
(2)
var myArray = [[10,20,30,40],
[100,200,300,400],
[1000,2000,3000,4000]];
]]>
オブジェクト配列
(オブジェクト)
<![CDATA[
function showAll() {
alert("Employee " + this.name + " is " + this.age + " years old.");
}
function coworker(name, age) {
this.name = name;
this.age = age;
this.show = showAll;
}
]]>
オブジェクトを配列に格納する方法は３種類。
<![CDATA[
(1)
var employeeDB = new Array();
employeeDB[employeeDB.length] = new coworker("Alice", 23);
employeeDB[employeeDB.length] = new coworker("Fred", 32);
employeeDB[employeeDB.length] = new coworker("Jean", 28);
employeeDB[employeeDB.length] = new coworker("Steve", 24);
(2)
var employeeDB = new Array();
employeeDB[employeeDB.length] = {name:"Alice", age:23, show:showAll};
employeeDB[employeeDB.length] = {name:"Fred", age:32, show:showAll};
employeeDB[employeeDB.length] = {name:"Jean", age:28, show:showAll};
employeeDB[employeeDB.length] = {name:"Steve", age:24, show:showAll};
(3)
var employeeDB = [{name:"Alice", age:23, show:showAll},
{name:"Fred", age:32, show:showAll},
{name:"Jean", age:28, show:showAll},
{name:"Steve", age:24, show:showAll}];
]]>
配列を使って、ある年齢の範囲のデータを検索。
<![CDATA[
var result = new Array();
for (var i = 0; i < employeeDB.length; i++) {
// 20歳から30歳の範囲を検索
if (employeeDB[i].age >= 20 && employeeDB[i].age <= 30) {
result = result.concat(employeeDB[i].name);
}
}
]]>
連想配列
上記オブジェクト配列から、連想配列(ハッシュテーブル)を作成。
<![CDATA[
for (var i = 0; i < employeeDB.length; i++) {
employeeDB[employeeDB[i].name] = employeeDB[i];
}
]]>
連想配列からの参照方法は
<![CDATA[
var age = employeeDB["Alice"].age;
]]>
要素の削除
置換メソッドspliceに、置換文字列を指定せずに呼び出す。
配列の１番目から３番目までの要素を削除する。
<![CDATA[
myArray = new Array(0,1,2,3,4,5,6);
p1 = 1;
p3 = 3;
myArray.splice(p1,p3);
]]>
