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Linear Search in JavaScript

Linear Search in JavaScript

Linear search, also known as sequential search, is an algorithm where we look for an item in a list by comparing each item one by one. It’s a straightforward algorithm that we use every day.

Example

Given an array arr = [4, 1, 3, 2] and we are looking for our target to search s = 3, we compare the values at each index one by one until it is found.

Linear Search Algorithm

Note

  • Linear search can be performed on both sorted and unsorted data
  • We return the index/position of the element if found else return -1 if not found

Linear Search Algorithm

LinearSearch(List, Value)
   for all items in the list
    if item == value
      return its position
 else return not foundCode language: JavaScript (javascript)

JavaScript Code

function linearSearch(arr, target) {
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] === target) {
      return i;
    }
  }
  return -1;
}

const arr = [4, 1, 3, 2, 5];
console.log(linearSearch(arr, 2));
// Output: 3 (i.e at index 3 of the array we have 2)

console.log(linearSearch([3.14, 2.71, 1.61, 0.57], 1.61));
// Output: 2

console.log(linearSearch(['apple', 'banana', 'cherry'], 'banana'));
// Output: 1

console.log(linearSearch([12, 3, 45, 6, 78], 100));
// Output: -1Code language: JavaScript (javascript)

Time Complexity: O(N)

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