1.push()
Syntax: array. Push (data)
Function: append data to the end of the array
Return value: the latest length of the array after appending data
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute push method var res=arr.push('Additional data') console.log(arr) console.log(res)
2.pop()
Syntax: array. pop()
Function: delete the last data of the array
Return value: deleted data
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute pop method var res=arr.pop() console.log(arr) console.log(res)
3.unshift()
Syntax: array. Unshift (data)
Function: append data to the front of the array
Return value: the latest length of the array after adding data
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute the unshift method var res=arr.unshift('ha-ha') console.log(arr) console.log(res)
4.shift()
Syntax: array. shift()
Function: delete the first data of the array
Return value: deleted data
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute the shift method var res=arr.shift() console.log(arr) console.log(res)
5.reverse()
Syntax: array. reverse()
Function: invert the array
Return value: array after inversion
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute the reverse method var res=arr.reverse() console.log(arr) console.log(res)
6.splice()
Syntax: array. Splice (start index, how many, data to insert)
---------Start index: default is 0
---------How many: the default is 0
---------Data to insert: none by default
Function: delete several data in the array and select whether to insert new data
Return value: returns the deleted data as a new array
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute the splice method var res=arr.splice(1,1) console.log(arr) console.log(res)
7.sort()
Syntax:
- Array. sort()
- Array. sort(function(a,b){return a-b})
- Array. sort(function(a,b){return b-a})
Function: sort arrays
Return value: sorted array
sort() ----------- sort by bit
//Prepare a raw array var arr=[4,6,8,2,33,11,22,15,48,9,6,23] //Output once console.log(arr) //Execute sort method var res=arr.sort() console.log(arr) console.log(res)
sort(function(a,b){return a-b}) --------- sort from small to large
//Prepare a raw array var arr=[4,6,8,2,33,11,22,15,48,9,6,23] //Output once console.log(arr) //Execute sort method var res=arr.sort(function(a,b){return a-b}) console.log(arr) console.log(res)
sort(function(a,b){return a-b}) --------- sort from large to small
//Prepare a raw array var arr=[4,6,8,2,33,11,22,15,48,9,6,23] //Output once console.log(arr) //Execute sort method var res=arr.sort(function(a,b){return b-a}) console.log(arr) console.log(res)
8.join()
Syntax: array. Join (connector)
Function: connect the array into a string with a connector
Return value: connected string
//Prepare a raw array var arr=[4,6,8,2,33] //Output once console.log(arr) //Execute join method var res=arr.join('*') console.log(arr) console.log(res)
9.concat()
Syntax: array. Concat (other arrays)
Function: splice other arrays and arrays together
Return value: spliced new array
//Prepare a raw array var arr=[4,6,8,2,33] //Output once console.log(arr) //Execute concat method var res=arr.concat([100,200]) console.log(arr) console.log(res)
10.slice()
Syntax: array. Slice (start index, end index)
- Start index: default is 0
- End index: the default is array length
Function: intercept some data in the array
Return value: returns the intercepted data in the form of a new array
//Prepare a raw array var arr=[4,6,8,2,33] //Output once console.log(arr) //Execute slice method var res=arr.slice(2,4) console.log(arr) console.log(res)
ps: before package, not after package
11.indexOf()
Syntax: array. Indexof (data)
Function: find the index position of data in the array
Return value:
- With this data, the index position of the first occurrence is returned
- If there is no such data, return * * - 1**
ps: uppercase O of indexOf()
//Prepare a raw array var arr=[4,6,8,2,33,1,6] //Output once console.log(arr) //Execute indexOf method var res=arr.indexOf(6) console.log(arr) console.log(res)
12.forEach()
Syntax: array. forEach(function(item,index,arr) {})
Function: traverse array
Return value: None
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute the forEach method var res=arr.forEach(function(item,index,arr){ console.log(item) console.log(index) console.log(arr) console.log('-----------------') })
13.map()
Syntax: array. map(function(item,index,arr) {})
Function: mapping array
Return value: new array after mapping
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute map method var res=arr.map(function(item,index,arr){ //Write the mapping condition as return return item*10 }) console.log(arr) console.log(res)
14.filter()
Syntax: array. filter(function(item,index,arr) {})
Function: filter array
Return value: new array after filtering
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute filter method var res=arr.filter(function(item,index,arr){ //Write the mapping condition as return return item>=300 }) console.log(arr) console.log(res)
15.every()
Syntax: array. every(function(item,index,arr) {})
Function: judge whether each item of the array meets the conditions
Return value: a Boolean value (false/true)
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute every method var res=arr.every(function(item,index,arr){ //Write the mapping condition as return return item>=300 }) console.log(arr) console.log(res)
16.some()
Syntax: array. some(function(item,index,arr) {})
Function: judge whether all items in the array meet the conditions
Return value: a Boolean value (false/true)
//Prepare a raw array var arr=[100,200,300,400] //Output once console.log(arr) //Execute some method var res=arr.some(function(item,index,arr){ //Write the mapping condition as return return item>=300 }) console.log(arr) console.log(res)
The above is the method of array operation commonly used in js. It is easy to understand, use and remember