Detailed explanation of HTML array_html/css_WEB-ITnose
Jun 24, 2016 am 11:45 AMArray
1. Array declaration:
1. One-dimensional array
var x=new Array();//Empty array
var x = new Array(size); //Array of specified length
var x = new Array(element 0,element 1,...); //Specify initial value,,,, does not limit the data type stored
Also: var x =["Xiao Ming", "Xiao Hong"];//Indicates one-dimensional array array elements----Xiao Ming, Xiao Hong
3] means that the length of the array x is 3; = {'you', 'good', 'ah'};arr[1] = {'you', 'true', 'beautiful'};
arr[2] = {'you' , 'are' , 'full'};
//Traverse the two-dimensional array
for(var i=0; i<arr.length; i )
{
for(var j=0; i<arr[i].length ; i )
Document.write(arr[i] [j] ” ”);
}
Document.write('<hr/>');
}
2. The length and subscript of the array
1. var a = new Array(); define a null pointer
But a subscript that exceeds the length of the array means changing the length of the array
2. a.length=5 (adding numbers directly changes the length------can be lengthened or shortened)
But alert (a[6]) will display undefined
3. Commonly used methods for arrays
Methods
Function
EG
| concat | Concatenates two or more arrays and returns the result | |
var c=a.concat(b);
| Join | Convert all elements of the array Put a character into the element | |
Var a=new Array(''a,'b'); a.join('"!")
| pop | Remove and return the last element of the array | |
a.pop();
| Push | Adds one or more elements to the end of the array and returns the new length | |
Returns the length
| Reverse | Reverse the order in the array | |
Return new array after inversion
| Shift | Delete and return array The first element of | |
removes and returns the removed element
| Slice | Return selected elements from an existing array | |
var arr = ["George","John","Thomas","James" ,"Adrew","Martin"]; | document.write(arr.slice(2,-2)); //Thomas,James//Negative numbers count from the back to -2 (i.e. the third to last number) |
Sort() Sort the elements of the array | |
The default is to sort according to the order of character encoding Parameter writing comparison function |
| splice
Delete elements and add new elements to the array | |
1. splice(index deleted position Negative numbers count backwards, howmany quantity, new1, add from deleted position, new2...) |
|
tostring Convert the array to a string and return the result | |
is designed for strings and automatically adds , number
| Unshift | Adds one or more elements to the beginning of the array and returns the new length |
|
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv ="Content-Type" content="text/html; charset=utf-8" />
<title>array</title>
<script type="text/javascript">
var a = new Array();
var name = prompt('Please enter a string, if you want to end, please enter "END" to end', 'END');//'END ' is the default filled content
a[a.length] = name;
} while (name != 'END');
a.length = a.length - 1;
alert( a);
var b = new Array();
b[0] = ["ni", "hao"];
b[1] = [3, 4 ];
//for (var i = 0; i < b.length; i )
// for (var j = 0; j < b[i].length; j )
// {> // document.write (b [i] [j] "& lt; br/& gt;")
//}
for (var I in b)
for (var j in b [i]) <[> {
Document.write (b [i] [j] "& lt; br/& gt;")
}
var b = new array ', 'overload', 'hit');
for (var i = 0; i < b.length; i ) {
alert(b[i]);
document.write(b.join("!"));
document.write("<br/>");
//pop() deletes the last An element and output the deleted array
document.write(b.pop());
//tostring() method;
var arr = new Array();
arr[0] = "George"
arr[1] = "John"
arr[2] = "Thomas"
arr[3] = "James"
arr[4] = "Adrew"
arr[5] = "Martin"
document.write(arr "<br/>");
//for(var i in arr :) toString();
document.write(c "<br/>");
document.write(c.replace(/,/g, "") "<br/>") ;//Remove after toString, number /,/g without adding g means to remove the first
document.write(arr "<br />")
//Sort
document.write(arr.sort());
.
document.write(arr.shift() "<br />");
document.write(arr);
//
shift
document.write(arr. shift());
document.write(arr);
for (var i in arr) {
document.write(i arr[i]);
}
Demo of two-dimensional array
for (var i = 0; i < arr.length; i ) {
for (var j = 0; j < arr[i].length; i ) {
document.write(arr[i][j] " ");
}
document.write('<hr/>');
}
</script>
</head>
<body>
</body>
</html>

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