What Is Deletion in Array in Data Structure?


Angela Bailey

In data structures, deletion refers to the process of removing an element from an array. It is an essential operation that allows us to modify and manipulate arrays efficiently. Understanding how deletion works is crucial for building efficient algorithms and optimizing code.

Deletion in Array

When we delete an element from an array, we typically want to remove a specific value at a given index. After the deletion, the size of the array decreases by one, and all the elements following the deleted element are shifted to fill the empty space.

To perform a deletion in an array, we need to follow these steps:

Step 1: Find the Element

We first need to locate the index of the element we want to delete. We can use different techniques depending on whether our array is sorted or unsorted.

  • If our array is sorted, we can use binary search or interpolation search to find the index of the element efficiently.
  • If our array is unsorted, we may need to traverse through each element until we find a match.

Step 2: Delete the Element

Once we have identified the index of the element we want to delete, we can proceed with its removal. We replace it with either a special value (e.g., -1) or shift all subsequent elements one position back.

Step 3: Shift Elements

If we choose to shift elements after deletion, all subsequent elements in the array must be moved back by one position. This ensures that there are no gaps left in between elements. The shifting process can be done using loops or other techniques like memmove() function in C/C++.

Deletion Complexity

The time complexity of deletion in an array depends on the location of the element to be deleted. Here are the complexities for different scenarios:

  • Deleting an element at the beginning or end of an array takes O(1) constant time since no shifting is required.
  • Deleting an element from a sorted array using binary search or interpolation search takes O(log n) time for finding the element and O(n) time for shifting elements.
  • Deleting an element from an unsorted array takes O(n) time on average, as we may need to traverse through all elements to find a match.

It is worth noting that deleting multiple elements from an array can have a higher complexity depending on the number of deletions required and their locations.


Deletion in arrays is a fundamental operation in data structures. Understanding how to delete elements efficiently is crucial for building optimized algorithms. By following the steps mentioned above, we can successfully delete elements from arrays and maintain their integrity.

Remember that deletion in arrays involves locating the element, removing it, and shifting subsequent elements if necessary. With proper understanding and implementation, you can perform deletions effectively in your code.

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