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Common methods of array

Concat () method

The concat () method is used to join two or more arrays.

This method does not change the existing array, but only returns a copy of the joined array.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" var arr2 = new Array (3) arr2 [0] = "James" arr2 [1] = "Adrew" arr2 [2] = "Martin" var arr3 = new Array (2) arr3 [0] = "William" arr3 [1] = "Franklin" [xss_clean] (arr.concat (arr2,arr3)) / / George,John,Thomas,James,Adrew,Martin,William,Franklinjoin () method

The join () method is used to put all the elements in the array into a string.

Elements are separated by a specified delimiter.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr.join (".")) / / George.John.Thomaspop () method

The pop () method deletes and returns the last element of the array.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr) / / George,John,Thomas [xss_clean] (arr.pop ()) / / Thomas [xss_clean] (arr) / / George,Johnpush () method

The push () method adds one or more elements to the end of the array and returns a new length.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr + "") / / George,John, xss_clean [XSS _ clean] (arr.push ("James") + ") [xss_clean] (arr) / / George,John,Thomas,Jamesreverse () method

The reverse () method is used to reverse the order of elements in an array.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr + ") / / George,John,Thomas [xss_clean] (arr.reverse ()) / / Thomas,John,Georgeshift () method

The shift () method removes the first element of the array from it and returns the value of the first element.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr + ") / / George,John, arr [XSS _ clean] (arr.shift () +") / / John,Thomasslice () method

The slice () method returns the selected element from an existing array.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr + ") / / George,John, Thomas [XSS _ clean] (arr.slice (1) +") / / John, Thomas [XSS _ clean] (arr) / / George,John,Thomassort () method

The sort () method is used to sort the elements of the array.

Function sortNumber (return a-b) {return a-b} var arr = new Array (6) arr [0] = "10" arr [1] = "5" arr [2] = "40" arr [3] = "25" arr [4] = "1000" arr [5] = "1" [xss_clean] (arr + ") / 10 xss_clean (arr.sort (sortNumber)) / 1 method

The splice () method adds / removes elements to / from the array and then returns the deleted elements.

Var arr = new Array (6) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" arr [3] = "James" arr [4] = "Adrew" arr [5] = "Martin" [xss_clean] (arr + ") / / George,John,Thomas,James,Adrew,Martinarr.splice (2d0," William ") [xss_clean] (arr +") / / George,John,William,Thomas,James,Adrew,MartintoSource () method

The toSource () method represents the source code of the object.

The original value is inherited by all objects derived from the Array object.

The toSource () method is usually called automatically by JavaScript in the background and does not appear explicitly in the code.

Function employee (name,job,born) {this.name=name;this.job=job;this.born=born;} var bill=new employee ("Bill Gates", "Engineer", 1985); [xss_clean] (bill.toSource ()); / / ({name: "Bill Gates", job: "Engineer", born:1985}) toString () method

The toString () method converts the array to a string and returns the result.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr.toString ()) / / George,John,ThomastoLocaleString () method

Converts an array to a local string.

Var arr = new Array (3) arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr.toLocaleString ()) / / George, John, Thomasunshift () method

The unshift () method adds one or more elements to the beginning of the array and returns a new length.

Var arr = new Array () arr [0] = "George" arr [1] = "John" arr [2] = "Thomas" [xss_clean] (arr + "") / / George,John, xss_clean [XSS _ clean] (arr.unshift ("William") + ") [xss_clean] (arr) / / William,George,John,ThomasvalueOf () method

The valueOf () method returns the original value of the Array object.

The original value is inherited by all objects derived from the Array object.

The valueOf () method is usually called automatically by JavaScript in the background and does not appear explicitly in the code.

ArrayObject.valueOf ()

To sum up (the tagged array method is more commonly used, you must master it skillfully)

If you think there are other useful, commonly used array methods, feel free to leave a message and communicate with me! For example, reduce method and so on!

Var result = [{subject: 'math', score: 10}, {subject:' chinese', score: 20}, {subject: 'english', score: 30}]; var sum = result.reduce (function (prev, cur) {return cur.score + prev;}, 0); console.log (sum) / / 60 Thank you for reading! This is the end of this article on "what are the common methods of JavaScript array?". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, you can share it for more people to see!

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