TypeScript Array(数组)

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TypeScript

var sites : string [ ] ; sites = [ " Google " , " Runoob " , " Taobao " ] console . log ( sites [ 0 ] ) ; console . log ( sites [ 1 ] ) ;

编译以上代码，得到以下 JavaScript 代码：

JavaScript

var sites ; sites = [ " Google " , " Runoob " , " Taobao " ] ; console . log ( sites [ 0 ] ) ; console . log ( sites [ 1 ] ) ;

输出结果为：

Google
Runoob

以下实例我们在声明时直接初始化：

TypeScript

var nums : number [ ] = [ 1 , 2 , 3 , 4 ] console . log ( nums [ 0 ] ) ; console . log ( nums [ 1 ] ) ; console . log ( nums [ 2 ] ) ; console . log ( nums [ 3 ] ) ;

编译以上代码，得到以下 JavaScript 代码：

JavaScript

var nums = [ 1 , 2 , 3 , 4 ] ; console . log ( nums [ 0 ] ) ; console . log ( nums [ 1 ] ) ; console . log ( nums [ 2 ] ) ; console . log ( nums [ 3 ] ) ;

输出结果为：

Array 对象

我们也可以使用 Array 对象创建数组。

Array 对象的构造函数接受以下两种值：

表示数组大小的数值。初始化的数组列表，元素使用逗号分隔值。

TypeScript

var arr_names : number [ ] = new Array ( 4 ) for ( var i = 0 ; i < arr_names . length ; i ++ ) { arr_names [ i ] = i * 2 console . log ( arr_names [ i ] )

编译以上代码，得到以下 JavaScript 代码：

JavaScript

var arr_names = new Array ( 4 ) ; for ( var i = 0 ; i < arr_names . length ; i ++ ) { arr_names [ i ] = i * 2 ; console . log ( arr_names [ i ] ) ;

输出结果为：

以下实例我们直接初始化数组元素：

TypeScript

var sites : string [ ] = new Array ( " Google " , " Runoob " , " Taobao " , " Facebook " ) for ( var i = 0 ; i < sites . length ; i ++ ) { console . log ( sites [ i ] )

编译以上代码，得到以下 JavaScript 代码：

JavaScript

var sites = new Array ( " Google " , " Runoob " , " Taobao " , " Facebook " ) ; for ( var i = 0 ; i < sites . length ; i ++ ) { console . log ( sites [ i ] ) ;

输出结果为：

Google
Runoob
Taobao
Facebook

TypeScript

var arr : number [ ] = [ 12 , 13 ] var [ x , y ] = arr // 将数组的两个元素赋值给变量 x 和 y console . log ( x ) console . log ( y )

编译以上代码，得到以下 JavaScript 代码：

JavaScript

var arr = [ 12 , 13 ] ; var x = arr [ 0 ] , y = arr [ 1 ] ; // 将数组的两个元素赋值给变量 x 和 y console . log ( x ) ; console . log ( y ) ;

输出结果为：

我们可以使用 for 语句来循环输出数组的各个元素：

TypeScript

var j : any ; var nums : number [ ] = [ 1001 , 1002 , 1003 , 1004 ] for ( j in nums ) { console . log ( nums [ j ] )

编译以上代码，得到以下 JavaScript 代码：

JavaScript

var j ; var nums = [ 1001 , 1002 , 1003 , 1004 ] ; for ( j in nums ) { console . log ( nums [ j ] ) ;

输出结果为：

一个数组的元素可以是另外一个数组，这样就构成了多维数组（Multi-dimensional Array）。

最简单的多维数组是二维数组，定义方式如下：

var arr_name:datatype[][]=[ [val1,val2,val3],[v1,v2,v3] ]

定义一个二维数组，每一个维度的数组有三个元素。

TypeScript

var multi : number [ ] [ ] = [ [ 1 , 2 , 3 ] , [ 23 , 24 , 25 ] ] console . log ( multi [ 0 ] [ 0 ] ) console . log ( multi [ 0 ] [ 1 ] ) console . log ( multi [ 0 ] [ 2 ] ) console . log ( multi [ 1 ] [ 0 ] ) console . log ( multi [ 1 ] [ 1 ] ) console . log ( multi [ 1 ] [ 2 ] )

编译以上代码，得到以下 JavaScript 代码：

JavaScript

var multi = [ [ 1 , 2 , 3 ] , [ 23 , 24 , 25 ] ] ; console . log ( multi [ 0 ] [ 0 ] ) ; console . log ( multi [ 0 ] [ 1 ] ) ; console . log ( multi [ 0 ] [ 2 ] ) ; console . log ( multi [ 1 ] [ 0 ] ) ; console . log ( multi [ 1 ] [ 1 ] ) ; console . log ( multi [ 1 ] [ 2 ] ) ;

输出结果为：

数组在函数中的使用

作为参数传递给函数

TypeScript

var sites : string [ ] = new Array ( " Google " , " Runoob " , " Taobao " , " Facebook " ) function disp ( arr_sites : string [ ] ) { for ( var i = 0 ; i < arr_sites . length ; i ++ ) { console . log ( arr_sites [ i ] ) disp ( sites ) ;

编译以上代码，得到以下 JavaScript 代码：

JavaScript

var sites = new Array ( " Google " , " Runoob " , " Taobao " , " Facebook " ) ; function disp ( arr_sites ) { for ( var i = 0 ; i < arr_sites . length ; i ++ ) { console . log ( arr_sites [ i ] ) ; disp ( sites ) ;

输出结果为：

Google
Runoob
Taobao
Facebook

作为函数的返回值

TypeScript

function disp ( ) : string [ ] { return new Array ( " Google " , " Runoob " , " Taobao " , " Facebook " ) ; var sites : string [ ] = disp ( ) for ( var i in sites ) { console . log ( sites [ i ] )

编译以上代码，得到以下 JavaScript 代码：

JavaScript

function disp ( ) { return new Array ( " Google " , " Runoob " , " Taobao " , " Facebook " ) ; var sites = disp ( ) ; for ( var i in sites ) { console . log ( sites [ i ] ) ;

输出结果为：

Google
Runoob
Taobao
Facebook

下表列出了一些常用的数组方法：

方法 & 描述 concat()

连接两个或更多的数组，并返回结果。

var alpha = ["a", "b", "c"]; var numeric = [1, 2, 3]; var alphaNumeric = alpha.concat(numeric); console.log("alphaNumeric : " + alphaNumeric ); // a,b,c,1,2,3 var numbers = new Array(1, 4, 9); var length = numbers.push(10); console.log("new numbers is : " + numbers ); // 1,4,9,10 length = numbers.push(20); console.log("new numbers is : " + numbers ); // 1,4,9,10,20 var arr = ["orange", "mango", "banana", "sugar", "tea"]; console.log("arr.slice( 1, 2) : " + arr.slice( 1, 2) ); // mango console.log("arr.slice( 1, 3) : " + arr.slice( 1, 3) ); // mango,banana var retval = [2, 5, 8, 1, 4].some(isBigEnough); console.log("Returned value is : " + retval ); // false var retval = [12, 5, 8, 1, 4].some(isBigEnough); console.log("Returned value is : " + retval ); // true var arr = ["orange", "mango", "banana", "sugar", "tea"]; var removed = arr.splice(2, 0, "water"); console.log("After adding 1: " + arr ); // orange,mango,water,banana,sugar,tea console.log("removed is: " + removed); removed = arr.splice(3, 1); console.log("After removing 1: " + arr ); // orange,mango,water,sugar,tea console.log("removed is: " + removed); // banana var arr = new Array("orange", "mango", "banana", "sugar"); var length = arr.unshift("water"); console.log("Returned array is : " + arr ); // water,orange,mango,banana,sugar console.log("Length of the array is : " + length ); // 5