## Related Articles

• Write an Interview Experience

# How to create an object from two arrays in JavaScript?

• Difficulty Level : Easy
• Last Updated : 27 Sep, 2022

Given two arrays the task is to create an object from them where the first array contains the keys of the object and the second array contains the values of the object. Return null if the array lengths are not the same or if the arrays are empty. An example of this problem in real life is, for example, you have got an array of roll number of students and an array of the name of the students which are in the same order, and you want to create an object so that you can access the student name using the roll number easily.

Example:

```Input:
Array 1 =>  [1, 2, 3, 4]
Array 2 =>  ["ram", "shyam", "sita", "gita"]

Output:
{
1: "ram",
2: "shyam",
3: "sita",
4: "gita"
}```

To solve this problem we have the following approaches:

Example 1: Using for-each loop.

## Javascript

 `let a = [1, 2, 3, 4];``let b = [``"ram"``, ``"shyam"``, ``"sita"``, ``"gita"``]` `// Checking if the array lengths are same``// and none of the array is empty`` ``function` `convertToObj(a, b){``  ``if``(a.length != b.length || a.length == 0 || b.length == 0){``   ``return` `null``;``  ``}``  ``let obj = {};``  ` `// Using the foreach method``  ``a.forEach((k, i) => {obj[k] = b[i]})``  ``return` `obj;``}``console.log(convertToObj(a, b))`

Output:

```{
1: "ram",
2: "shyam",
3: "sita",
4: "gita"
}```

Example 2: Using Object.assign method.

## Javascript

 `let a = [1, 2, 3, 4];``let b = [``"ram"``, ``"shyam"``, ``"sita"``, ``"gita"``]` `// Checking if the array lengths are same``// and none of the array is empty`` ``function` `convertToObj(a, b){``  ``if``(a.length != b.length || a.length == 0 || b.length == 0){``    ``return` `null``;``  ``}`` ` `// Using Object.assign method``  ``return` `Object.assign(...a.map((k, i)=>({[k]: b[i]}) ))``}``console.log(convertToObj(a, b))`

Output:

```{
1: "ram",
2: "shyam",
3: "sita",
4: "gita"
}```

Example-3: Using reduce() method.

## Javascript

 `let a = [1, 2, 3, 4];``let b = [``"ram"``, ``"shyam"``, ``"sita"``, ``"gita"``];` `// Checking if the array lengths are same``// and none of the array is empty``function` `convertToObj(a, b) {``  ``if` `(a.length != b.length || a.length == 0 || b.length == 0) {``    ``return` `null``;``  ``}` `  ``// Using reduce() method``  ``let object = a.reduce((acc, element, index) => {``    ``return` `{``      ``...acc,``      ``[element]: b[index],``    ``};``  ``}, {});` `  ``return` `object;``}``console.log(convertToObj(a, b));` `// This code is contributed by Aman Singla...`

Output:  Here in output we will experience keys of an object in string format by default.

```{
'1': 'ram',
'2': 'shyam',
'3': 'sita',
'4': 'gita'
}```

My Personal Notes arrow_drop_up