understanding_array_methods

Write in your own way of understanding

1.Data types of parameters

2.Return value type

3.Write three examples

4.In your words what this method does.

5.Does it mutate the original value or not

1. Concat

1.Parameters: n (any) number of values (number, string, boolean, array, null, undefined, object and function etc)

2.Return: a single Array consisting of by all the values passed as parameters in the same order.

3.Write three examples:

    let numbers = [1, 2, 3];
    numbers.concat(4); //[1,2,3,4]

    let sentanceArray = 'A quick brown fox jumped over a lazy'.split(' ');
    sentanceArray.concat('dog').join(' '); //"A quick brown fox jumped over a lazy dog"

    let colors = ['red', 'green', 'blue'];
    colors.concat('black', 'red', 21, true); // ['red','green','blue','black', 'red', 21, true]

4. Explain: concat accepts n number of values and returns one array with all the values in same order. It does not change the original array.

5.Does it mutate the original value or not: No it does not mutate the original array

2. Join

1.Parameters: input with Separater which separate element of array

2.Return: Return new array with separater

3.Examples:

    let users = ["Arya","jon"."Stark"]
    console.log(users.join(`++`)); // "Arya++jon++Stark"
    let users = ["Arya","jon"."Stark"]
    console.log(users.join(``)); // "AryajonStark"
    let users = ["4","3","2"]
    console.log(users.join(`+`)); //4+3+2;

4.Join all elements of array in one string with separater, if any.

5. It does't mutate. It create new string.

2. Join

1.Parameters: input with Separater which separate element of array

2.Return: Return new array with separater

3.Examples:

    let users = ["Arya","jon"."Stark"]
    console.log(users.join(`++`)); // "Arya++jon++Stark"
    let users = ["Arya","jon"."Stark"]
    console.log(users.join(``)); // "AryajonStark"
    let users = ["4","3","2"]
    console.log(users.join(`+`)); //4+3+2;

4.Join all elements of array in one string with separater, if any.

5. It does't mutate. It create new string.

3. flat

1.Parameters: It take input as number of array want to join

2.Return: Return new array with all elements.

3.Examples:

    let users = ["Arya",["jon",["Stark"]]];
    console.log(users.flat(2)); //["Arya", "jon", "Stark"]
    let numbers = [1,[2,[3,[4,[5,6]]]]]
    numbers.flat(Infinity); // [1, 2, 3, 4, 5, 6]

4.Join all elements of array in new array as defined in parameter,

5. It does't mutate.

4. push

1.Parameters: The element to add to end of the array

2.Return: Lenght of array with added element at last.

3.Examples:

    let users = ["Arya","jon","Stark"];
    users.push("dragon"); //["Arya", "jon", "Stark". "dragon"]
    let numbers = [1,2,3,4,5,6]
    numbers.push(8); // [1, 2, 3, 4, 5, 6,8]

4.Add elements at end of array which is defined in parameter, to show elements call array.

5. It mutate.

5. indexOf

1.Parameters: Element to called in array

2.Return: Index of called elements

3.Examples:

    let users = ["Arya","jon","Stark","dragon"];
    users.indexOf("dragon"); // 3
    let numbers = [1,2,3,4,5,6,8]
    numbers.indexOf(8); //   6

4.Show index of called elements, -1 if not found

5. It does,t mutate.

6. lastindexOf

1.Parameters: Element to called in array

2.Return: last index of called elements

3.Examples:

    let users = ["Arya","jon","Stark","dragon","Arya"];
    users.lastIndexOf("Arya"); // 4
    let numbers = [1,2,3,4,5,6,8,6,4]
    numbers.indexOf(6); //   7

4.Show index of called elements, -1 if not found

5. It does,t mutate.

7. includes

1.Parameters: value to search for

2.Return: Return in boolean

3.Examples:

    let users = ["Arya","jon","Stark","dragon","Arya"];
    users.includes("Arya"); // True
    let numbers = [1,2,3,4,5,6,8,6,4]
    numbers.includes(9); //   False

4.Returb in boolean, elements included in array or not.

5. It does,t mutate.

8. reverse

1.Parameters:

2.Return: reverse the array, and show their index

3.Examples:

    let users = ["Arya","jon","Stark","dragon","Arya"];
    users.reverse(); // ["Arya", "dragon", "Stark", "jon", "Arya"]
    let numbers = [1,2,3,4,5,6,8,6,4]
    numbers.reverse(); //  [4, 6, 8, 6, 5, 4, 3, 2, 1]

4.It reverse array

5. It mutate.

9. every

1.Parameters: value,

2.Return: in boolean

3.Examples:

    function isGreaterthen10(numbers) {
        return numbers >10;
    };
    let numbers = [1,2,3,4,5,6,8,6,4]
    numbers.every(isGreaterthen10); //  false

4.If called value in present in every elements of array, it will return in boolean value

5. It doesn't mutate.

10. shift

1.Parameters:

2.Return: deleted value

3.Examples:

    let numbers = [1,2,3,4,5,6,8,6,4]
    numbers.shift(); //  1

4. It delete first value of array and show that value in return. If array is called it show updated array without first value

5. It mutate.

11. splice

1.Parameters: Change and delete character at given index

2.Return: deleted value

3.Examples:

    let users = ["Arya","jon","Stark","dragon"];
    users.splice(2,1); //  ["Stark"]

4. It delete called value of array and show that value in return. If array is called it show updated array without called value

5. It mutate.

12. find

1.Parameters: callback Function include,elements,index and array

2.Return: only one value

3.Examples:

    let users = ["Arya","jon","Stark","dragon"];
    function isArya(users) {
        return users === "Arya"
    }
    let findReturn = users.find(isArya); // Arya
    let numbers = [1,3,5,7,9,12,20,200]
    function greaterThanEight(numbers) {
        return numbers > 8
    }
    let findNumber = numbers.find(greaterThanEight)  // 9

4. It is callbackFn which return only one(first) value which is called in find method

5. It doesn't mutate.

13. unshift

1.Parameters:

2.Return: add value in starting of array

3.Examples:

    let numbers = [1,2,3,4,5,6,8,6,4]
    numbers.unshift(32); //  10   //[32,1,2,3,4,5,6,8,6,4]

4. It add value in starting of array and return index of array. If array is called it show updated array with first value

5. It mutate.

14. find

1.Parameters: callback Function include,elements,index and array

2.Return: only one value

3.Examples:

    let users = ["Arya","jon","Stark","dragon"];
    function isArya(users) {
        return users === "Arya"
    }
    let findReturn = users.findIndex(isArya); // 0
    let numbers = [1,3,5,7,9,12,20,200]
    function greaterThanEight(numbers) {
        return numbers > 
    }
    let findNumber = numbers.findindex(greaterThanEight)  // 4

4. It is callbackFn which return index of only one(first) value which is called in findIndex method

5. It doesn't mutate.

15. filter

1.Parameters: callback Function include,elements,index and array

2.Return: new array which pass the test

3.Examples:

    let users = ["Arya","jon","Stark","dragon"];
    function islenghtMoreThanThree(users) {
        return users.lenght > 3
    }
    let return = users.filter(islenghtMoreThanThree); // ["Arya", "Stark", "dragon"]

    let numbers = [1,3,5,7,9,12,20,200]
    function greaterThanEight(numbers) {
        return numbers > 8
    }
    let filterNumber = numbers.filter(greaterThanEight)  // [9, 12, 20, 200]

4. It is callbackFn which return new array which pass the test, if not, return empty array.

5. It doesn't mutate.

16. flat

1.Parameters: how deep a nesting array should be flattened

2.Return: new array with called array concatenated in it

3.Examples:

    let numbers = [1,3,[5,7,[9,12,[20,200]]]]
    numbers.flat(2)  // [1, 3, 5, 7, 9, 12, Array(2)]
    numbers.flat(infinity)  // [1, 3, 5, 7, 9, 12, 20, 200]

4. It accept value and flattened called level of array. if infinity, flat all nesting of array.

5. It doesn't mutate.

15. forEach

1.Parameters: callback Function execute on each elements, accept 3 arguments - elements,index and array

2.Return: undefined, if no value

3.Examples:

    let users = ["Arya","jon","Stark","dragon"];
    function islenghtMoreThanThree(users) {
        return users.length > 3
    }
    let finalReturn = users.forEach(islengthMoreThanThree); ["Arya", "Stark", "dragon"]
     //

    let numbers = [1,3,5,7,9,12,20,200]
    function greaterThanEight(numbers) {
        return numbers > 8
    }
    let filterNumber = numbers.forEach(greaterThanEight)  // [9, 12, 20, 200]

4. It is callbackFn which return undefined but it return value when called in new array.

5. It doesn't mutate.

18. map

1.Parameters: callback Function execute on each elements, accept 3 arguments - elements,index and array

2.Return: new array which pass the test

3.Examples:

    let users = ["Arya","jon","Stark","dragon"];
    function islenghtMoreThanThree(users) {
        return users.length > 3
    }
    let finalReturn = users.forEach(islengthMoreThanThree); ["Arya", "Stark", "dragon"]
     //

    let numbers = [1,3,5,7,9,12,20,200]
    function greaterThanEight(numbers) {
        return numbers > 8
    }
    let filterNumber = numbers.forEach(greaterThanEight)  // [9, 12, 20, 200]

4. It is callbackFn which return new array.

5. It doesn't mutate.

19. pop

1.Parameters: The element to remove from end of the array

2.Return: Lenght of array after removing element from last.

3.Examples:

    let users = ["Arya","jon","Stark", "dragon"];
    users.pop(); //["Arya", "jon", "Stark"]
    let numbers = [1,2,3,4,5,6,8]
    numbers.pop(); // [1, 2, 3, 4, 5, 6]

4.remove elements from end of array which is defined in parameter

5. It mutate.

20. reduce

1.Parameters: accc, num

2.Return: Add of called value

3.Examples:

    let numbers = [1,2,3,4,5,6,8,6,4]
    function reducer(acc, num){
        return acc + num
    }
    numbers.reduce(reducer); // 39

4.it is call back function,which accept accumulator and value and add calledvalue

5. It doesn't mutate.

21. slice

1.Parameters: index and number of elements want to slice

2.Return: new sliced arrray

3.Examples:

    let numbers = [1,2,3,4,5,6,8,6,4]
    numbers.slice(2,2); // [1,2,5,6,8,6,4]

4.it accept index and number of elements want to slice and return that value in new array.

5. It doesn't mutate.

22. some

1.Parameters: value,

2.Return: in boolean

3.Examples:

    let numbers = [1,2,3,4,5,6,8,6,4]

    function isGreaterthen10(numbers) {
        return numbers >10;
    };

    numbers.some(isGreaterthen10); //  true

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README.md

Write in your own way of understanding

1.Data types of parameters

2.Return value type

3.Write three examples

4.In your words what this method does.

5.Does it mutate the original value or not

1. Concat

1.Parameters: n (any) number of values (number, string, boolean, array, null, undefined, object and function etc)

2.Return: a single Array consisting of by all the values passed as parameters in the same order.

3.Write three examples:

4. Explain: concat accepts n number of values and returns one array with all the values in same order. It does not change the original array.

5.Does it mutate the original value or not: No it does not mutate the original array

2. Join

1.Parameters: input with Separater which separate element of array

2.Return: Return new array with separater

3.Examples:

4.Join all elements of array in one string with separater, if any.

5. It does't mutate. It create new string.

2. Join

1.Parameters: input with Separater which separate element of array

2.Return: Return new array with separater

3.Examples:

4.Join all elements of array in one string with separater, if any.

5. It does't mutate. It create new string.

3. flat

1.Parameters: It take input as number of array want to join

2.Return: Return new array with all elements.

3.Examples:

4.Join all elements of array in new array as defined in parameter,

5. It does't mutate.

4. push

1.Parameters: The element to add to end of the array

2.Return: Lenght of array with added element at last.

3.Examples:

4.Add elements at end of array which is defined in parameter, to show elements call array.

5. It mutate.

5. indexOf

1.Parameters: Element to called in array

2.Return: Index of called elements

3.Examples:

4.Show index of called elements, -1 if not found

5. It does,t mutate.

6. lastindexOf

1.Parameters: Element to called in array

2.Return: last index of called elements

3.Examples:

4.Show index of called elements, -1 if not found

5. It does,t mutate.

7. includes

1.Parameters: value to search for

2.Return: Return in boolean

3.Examples:

4.Returb in boolean, elements included in array or not.

5. It does,t mutate.

8. reverse

1.Parameters:

2.Return: reverse the array, and show their index

3.Examples:

4.It reverse array

5. It mutate.

9. every

1.Parameters: value,

2.Return: in boolean

3.Examples:

4.If called value in present in every elements of array, it will return in boolean value

5. It doesn't mutate.

10. shift

1.Parameters:

`2. Join`

`3. flat`

`4. push`

`5. indexOf`

`6. lastindexOf`

`7. includes`

`8. reverse`

`9. every`

`10. shift`

`11. splice`

`12. find`

`13. unshift`

`14. find`

`15. filter`

`16. flat`

`15. forEach`

`18. map`

`19. pop`

`20. reduce`

`21. slice`