JavaScript陣列的3個屬性和14個方法
- 屬性
- constructor:回傳對創建此物件的陣列函式的參考,
- length:設定或回傳陣列中元素的數目,
- prototype:使您有能力向物件添加屬性和方法,
- 方法
- concat():連接兩個或更多的陣列,并回傳結果,
- join():把陣列的所有元素放入一個字串,元素通過指定的分隔符進行分隔,
- pop():洗掉并回傳陣列的最后一個元素
- push():向陣列的末尾添加一個或更多元素,并回傳新的長度,
- reverse():顛倒陣列中元素的順序,
- shift():洗掉并回傳陣列的第一個元素
- slice():從某個已有的陣列回傳選定的元素
- sort():對陣列的元素進行排序
- splice():洗掉元素,冰箱陣列添加新元素
- toSource():回傳該物件的源代碼
- toString():把陣列轉換為字串,并回傳結果
- toLocaleString():把陣列轉換為本地陣列,并回傳結果
- unshift():像陣列的開頭添加一個或者更多的元素,并且回傳性的陣列長度
- valueOf():回傳陣列物件的原始值,
屬性
constructor:回傳對創建此物件的陣列函式的參考,
constructor屬性是回傳對創建此物件的陣列函式的參考
<script type="text/javascript">
var test=new Array();
if (test.constructor==Array)
{
document.write("This is an Array");
}
if (test.constructor==Boolean)
{
document.write("This is a Boolean");
}
if (test.constructor==Date)
{
document.write("This is a Date");
}
if (test.constructor==String)
{
document.write("This is a String");
}
</script>
輸出結果為:
This is an Array
length:設定或回傳陣列中元素的數目,
length屬性是設定或回傳陣列中的元素的數目
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "John"
arr[1] = "Andy"
arr[2] = "Wendy"
document.write("Original length: " + arr.length)
document.write("<br />")
arr.length=5
document.write("New length: " + arr.length)
</script>
輸出結果為:
Original length: 3
New length: 5
prototype:使您有能力向物件添加屬性和方法,
prototype屬性是相對想添加屬性和方法
<script type="text/javascript">
function employee(name,job,born)
{
this.name=name;
this.job=job;
this.born=born;
}
var bill=new employee("Bill Gates","Engineer",1985);
employee.prototype.salary=null;
bill.salary=20000;
document.write(bill.salary);
</script>
輸出結果為:
20000
方法
concat():連接兩個或更多的陣列,并回傳結果,
concat()方法是連接兩個或者多個的陣列,并回傳結果
<script type="text/javascript">
var a = [1,2,3];
document.write(a.concat(4,5));
</script>
輸出結果為:
1,2,3,4,5
join():把陣列的所有元素放入一個字串,元素通過指定的分隔符進行分隔,
join()方法是把陣列的所有元素放入一個字串,通過指定的分隔符進行分隔
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr.join())
</script>
輸出結果為:
George,John,Thomas
pop():洗掉并回傳陣列的最后一個元素
pop()方法是洗掉并回傳陣列的最后一個元素
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr)
document.write("<br />")
document.write(arr.pop())
document.write("<br />")
document.write(arr)
</script>
輸出結果為:
George,John,Thomas
Thomas
George,John
push():向陣列的末尾添加一個或更多元素,并回傳新的長度,
push()方法是向陣列的末尾添加一個或更多元素,并回傳新的長度,
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr + "<br />")
document.write(arr.push("James") + "<br />")
document.write(arr)
</script>
輸出結果為:
George,John,Thomas
4
George,John,Thomas,James
reverse():顛倒陣列中元素的順序,
reverse()方式是顛倒陣列中元素的順序
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr + "<br />")
document.write(arr.reverse())
</script>
輸出結果為:
George,John,Thomas
Thomas,John,George
shift():洗掉并回傳陣列的第一個元素
shift()方法是洗掉并放回陣列的第一個元素
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr + "<br />")
document.write(arr.shift() + "<br />")
document.write(arr)
</script>
輸出結果為:
George,John,Thomas
George
John,Thomas
slice():從某個已有的陣列回傳選定的元素
slice()方法是從某個已有的陣列回傳選定的元素
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr + "<br />")
document.write(arr.slice(1) + "<br />")
document.write(arr)
</script>
George,John,Thomas
John,Thomas
George,John,Thomas
sort():對陣列的元素進行排序
sort()方式是對陣列的元素進行排序
<script type="text/javascript">
var arr = new Array(6)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
arr[3] = "James"
arr[4] = "Adrew"
arr[5] = "Martin"
document.write(arr + "<br />")
document.write(arr.sort())
</script>
輸出結果為:
George,John,Thomas,James,Adrew,Martin
Adrew,George,James,John,Martin,Thomas
splice():洗掉元素,冰箱陣列添加新元素
splice()方法是洗掉元素,并向陣列添加新元素
舉例:創建一個新陣列,并將其添加一個元素
<script type="text/javascript">
var arr = new Array(6)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
arr[3] = "James"
arr[4] = "Adrew"
arr[5] = "Martin"
document.write(arr + "<br />")
arr.splice(2,0,"William")
document.write(arr + "<br />")
</script>
輸出結果為:
George,John,Thomas,James,Adrew,Martin
George,John,William,Thomas,James,Adrew,Martin
舉例:洗掉位于i[2]的元素,并添加一個新的元素來替換被洗掉的元素
<script type="text/javascript">
var arr = new Array(6)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
arr[3] = "James"
arr[4] = "Adrew"
arr[5] = "Martin"
document.write(arr + "<br />")
arr.splice(2,1,"William")
document.write(arr)
</script>
輸出結果為:
George,John,Thomas,James,Adrew,MartinGeorge,John,William,James,Adrew,Martin
toSource():回傳該物件的源代碼
toSource()方法是回傳該物件的源代碼
<script type="text/javascript">
function employee(name,job,born)
{
this.name=name;
this.job=job;
this.born=born;
}
var bill=new employee("Bill Gates","Engineer",1985);
document.write(bill.toSource());
</script>
輸出結果為:
({name:"Bill Gates", job:"Engineer", born:1985})
toString():把陣列轉換為字串,并回傳結果
toString()方法是把陣列轉換為字串,并回傳結果
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr.toString())
</script>
輸出結果為:
George,John,Thomas
toLocaleString():把陣列轉換為本地陣列,并回傳結果
toLocaleString()方法把陣列轉換為本地陣列,并回傳結果
<script type="text/javascript">
var arr = new Array(3)
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr.toLocaleString())
</script>
輸出結果為:
George, John, Thomas
unshift():像陣列的開頭添加一個或者更多的元素,并且回傳性的陣列長度
unshift()方法是像陣列的開頭添加一個或者更多的元素,并且回傳性的陣列長度
<script type="text/javascript">
var arr = new Array()
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
document.write(arr + "<br />")
document.write(arr.unshift("William") + "<br />")
document.write(arr)
</script>
輸出結果:
George,John,Thomas
4
William,George,John,Thomas
valueOf():回傳陣列物件的原始值,
valueOf()方法回傳陣列物件的原始值,
語法:
arrayObject.valueOf()
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