Linear Search: Definition, Explanation & Examples

What is the linear search?

The linear search is a simple algorithm for searching data structures in which the elements are checked one after the other from start to finish. It is often used to find a specific element in a list or an array.

How does the linear search work?

In a linear search, each element of the data structure is checked in the order in which they are stored. The algorithm starts with the first element and compares it with the value being searched for. If the element is found, the algorithm returns the position of the element. Otherwise, the next element is checked until either the element is found or the end of the data structure is reached.

Linear search algorithm

1. Start with the first element in the list.
2. Compare the current element with the searched value.
3. If they match, return the position of the element.
4. If they do not match, go to the next element.
5. Repeat these steps until the element is found or the end of the list is reached.

Advantages and disadvantages of the linear search

Advantages

• Easy to implement.
• No data structure requirements (can be used with unsorted and sorted data).
• Well suited for small data sets.

Disadvantages

• Efficient only with small or unsorted data sets.
• The runtime is O(n), which means that the search time increases with the number of elements in the list.

Use cases of the linear search

Linear search is often used in simple applications where the amount of data is small or unsorted. Examples include:

• Searching for an element in a small list.
• Checking whether a specific value is present in a user input.
• Error diagnosis in small data sets where sorting the data would complicate the process.

Illustrative example on the topic: Linear search

Imagine you have a box of letters and each letter has a name on the front. You are looking for a specific letter that has the name "Max". Instead of sorting all the letters according to a certain pattern, you simply start by taking the first letter and checking it. If it is not "Max", set it aside and take the next letter. You repeat this process until you have found Max's letter or have checked all the letters.

Conclusion

Linear search is a versatile tool in programming that, while not the most efficient method for large amounts of data, can be useful in many everyday applications. Its simplicity and the ability to implement it without special data structure requirements make it a basic algorithm that every programmer should understand.

If you want to learn more about other search algorithms, read about binary search and comparison of search algorithms.