js array of methods and classification

 

Method name	The corresponding version	Features	Whether to change the original array
pop()	ES5-	Delete the last digit, and returns the deleted data	Y
shift()	ES5-	Delete the first one, and returns the deleted data	Y
unshift()	ES5-	Add one or more data in the first place, returns the length	Y
push()	ES5-	Add one or more data in the last one, the length of the return	Y
reverse()	ES5-	Reverse list, returns the result	Y
sort()	ES5-	Sort (character rules), returns the result	Y
splice()	ES5-	Delete the specified location, and replaced, return the deleted data	Y
toString()	ES5-	Directly into a string and returns	n
valueOf()	ES5-	Returns an array of object's original value	n
indexOf()	ES5	Query and return data index	n
lastIndexOf()	ES5	Reverse query and return data index	n
forEach()	ES5	Parameters for the callback function will traverse an array of all the items, the callback function takes three parameters, Respectively, value, index, self; forEach no return value	n
map()	ES5	With forEach, while the callback function returns data to form a new array returned by the map	n
filter()	ES5	With forEach, while the callback function returns a Boolean value of true data returned by the filter to form a new array	n
every()	ES5	With forEach, while the callback function returns a Boolean value, all true, returned by every true	n
some()	ES5	With forEach, while the callback function returns a Boolean value, as long as one of the true, returned by some true	n
reduce()	ES5	Merge, all with forEach, iterative array and constructs a final value returned by reduce	n
reduceRight()	ES5	Reverse merger, all with forEach, iterative array and constructs a final value returned by reduceRight	n
concat()	ES5-	Data after the merge array, and returns the merged	n
join()	ES5-	Delimiters, and returns the array into a string	n
slice()	ES5-	Array taken specified position, and returns	n

An operation to change so that the original array

 

1. increasing array

　　unshift(data1,data2...) 

　　Increasing the number of elements to the first array and returns the new length

var arr = [1,2,3];
var str = arr.unshift(0,0,0);       
console.log(str);　　　　　　　　　//6(length)

console.log(arr); 　　　　　　　　// [0, 0, 0, 1, 2, 3]

 　　push(data1,data2...)

　　Increasing the number of array elements to the last one, returns the new length

var arr = [1,2,3];
var str = arr.push(6,6,6);      
console.log(str);　　　　　　　 //6(length)

console.log(arr); //  [1, 2, 3, 6, 6, 6]

 2. Delete the array

　　shift()

　　Remove and return the foremost element of an array

var arr = [1,2,3 ]; 
console.log (arr.pop ());     // 1 (元素) 
console.log (arr);           // [2,3]

　　pop()

　　Remove and return the last element of an array

var arr = [1,2,3 ]; 
console.log (arr.pop ());     // 3 (元素) 
console.log (arr);           // [1,2]

 3. To change the array

　　splice (start, n, data1, data2 ...) optional parameters

　　Delete elements in the array, and add new elements

 var arr = ["A","B","C","D","E"];    
console.log(arr.splice(2,0,"a","b"));  //[]
console.log(arr);    //["A", "B", "a", "b", "C", "D", "E"] 原数组改变

 

　　sort()

　　Sort the array of elements (characters method), the default is ascending

var ARR = [ . 4 , 2 , . 3 , . 5 , . 1 ]; 
the console.log (arr.sort ());     // [. 1, 2,. 3,. 4,. 5] 
the console.log (ARR);            // [. 1 , 2, 3, 4, 5] to change the original array

　　reserve()

　　Reverse the order of elements in the array

var ARR = [ . 1 , 2 , . 3 ]; 
the console.log (arr.reverse ());      // [3,2,1] 
the console.log (ARR);                // [3,2,1] changes the original array

 

II. Does not change the original array

1.slice(m,n)

　M start bits taken from the n-bit elements

When n omitted, or n = 0, until the last one element selected;

m <0 or n <0, the last bit indicates the start date

 

var arr = ["A","B","C","D","E"];
console.log(arr.slice(1,3));         //["B","C"]
console.log(arr.slice(1));           //["B","C","D","E"]
console.log(arr.slice(-4,-1));       //["B","C","D"]
console.log(arr.slice(-2));          //["D","E"]
console.log(arr.slice(1,-2));        //["B","C"]
console.log(arr);                    //["A","B","C","D","E"]

 

2.toString()

　　The array is converted to character

var arr=["夜","的","第","七","章"] ;
var str=arr.toString();
console.log(str);

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