Most used Array Methods in JS
Hello Everyone 👋 ,
I will be sharing the list of most used array methods in JS that are used every now and then in Array data manipulation .
Lets's Start !!
1. toString()
The first method in the list is toString() , it is used to list down all the elements in the array as comma seperated string.
let arrayOfIntegers =[1,2,3,4,5] ;
console.log(arrayOfIntegers.toString()) // 1,2,3,4,5
2. sort()
The second method in the list is sort() , using which we can sort the array elements but the sorting is done alphabetical manner . That means "2" >"1" , "a" > "A" and also "2" >"100". Let's understand this with an example below :
let arrayOfIntegers = [1,2,3,4,5,100,20] ;
arrayOfIntegers.sort();
console.log(arrayOfIntegers); // [1,100,2,20,3,4,5]
To solve this problem of sorting for integers , JS has compare function's to sort them correctly. What compare function does for us is , it will compare the values passed inside the function and return a value based on which the data is sorted . e.g., if a> b then , a is placed after b , if a<b then a is placed before b , else they are equal.
/* To solve this problem of sorting for integers , JS<br> has compare function's to sort them correctly*/
let arrayOfIntegers =[1,2,3,4,5,100,20] ;
arrayOfIntegers.sort(function(a,b) {return a-b});
console.log(arrayOfIntegers) // [1,2,3,4,5,20,100]
/* To sort in descending order */
arrayOfIntegers.sort(function(a,b) {return b-a});
console.log(arrayOfIntegers) // [100,20,5,4,3,2,1]
3. join()
Moving forward , we have join() which will return the array elements as string joined with the value provided as parameter in join(). This method does not change the original array , instead return a string value.
let arr = ["happy" , "coding"];
console.log(arr.join("-")); // happy-coding
let value = arr.join("*");
console.log(typeof value); // string
4. from()
This method is used to convert the object to the Array but with one condition , ie., the object to be converted must have the length property associated to it . e.g., strings.
let str="ABC";
let arr = Array.from(str);
console.log(arr); // ['A' , 'B' , 'C']
5. reverse()
This method is used to print the array elements in reverse order ,i.e., elements are printed from rigth to left .
let arr=[1,5,8,9,12,3,7];
arr.reverse();
console.log(arr); // [ 7, 3, 12, 9, 8, 5, 1]
6. splice()
This method is used to add elements in an array at the specified positon . Synatx :- splice(start_index , count of elements to remove , elements to be added ) . More than one elements can also be added by providing comma seperated values as last param's.
let arr = [1,10,20,30];
arr.splice(2,0,5);
console.log(arr); // [1,10,5,20,30]
arr.splice(1,0,3,4);
console.log(arr); // [1,3,4,10,5,20,30]
/*The elements are inserted at specified index (param1) in an array and deletes the no. of elements (param2) from array*/
arr.splice(5,2,6,7);
console.log(arr) // [1,3,4,10,5,6,7]
Splice can also be used to only remove elements from an array instead of adding them to array.
/* taking advantage of the fact that third parameter in
splice is optional , we can remove elements from specified index*/
let arr=[1,3,4,10,5,6,7] ;
arr.splice(1,2);
console.log(arr) // [ 1, 10, 5, 6, 7 ]
/*removes 2 elements starting from index 1 */
7. slice()
This method is used to extract the array elements from the array . This methods returns the sliced array from original array . Syntax :- slice(start_index,last_index) , where start_index is inclusive and last_index is exclusive.
let arr = [1,5,10,15,20];
let newArr= arr.slice(1,3);
console.log(arr); // [1,5,10,15,20]
console.log(newArr); // [5,10]
I hope this article will help you understand the basic operations performend on arrays using the above methods.
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