binary search in python

What is Python? | Binary Search in Python

What is Python? | Binary Search in Python. Learn how Python binary search works. Find out when the binary search is an appropriate choice for solving problems based on its time complexity and limitations.


By repeatedly dividing a sorted list in half until the element is found or it is clear that the element is not present, binary search is an efficient algorithm for finding an element within that list. Binary search is much faster than linear search, which checks each element until the target element is found.

What is Python?

In addition to web development, data analysis, artificial intelligence, and scientific computing, Python is a high-level, interpreted programming language. Beginning programmers and experienced programmers alike like it because of its simplicity, readability, and flexibility.

A popular programming language with a large community of users and developers, Python was created in the late 1980s by Guido van Rossum and has become one of the most popular programming languages in the world.

Its standard library includes modules for working with data, networks, and operating systems, along with tools for scientific computing, machine learning, and artificial intelligence. Additionally, it can be extended and customized using a variety of third-party libraries and frameworks.

  1. Interpreted language:

A Python program can run on any platform that has a Python interpreter installed, as Python is an interpreted language that executes at runtime rather than being compiled into machine code.

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What is the process of binary search?

The algorithm begins by comparing the target element to the middle element of the list. Once the list has been sorted in ascending order, a binary search can be performed. If the target element is smaller than the middle element, the algorithm searches the left half of the list. In case the target element is larger than the middle element, the algorithm searches the right half. A repeat of this process is performed until the target element is found or it is clear that the element is not present in the list.

  1. Python Binary Search Implementation

Here’s the method to implement binary search in Python. 

  1. Bisect Module:

A binary search and sorted list can be performed with the bisect module, which provides binary search and sort functions.

Example to implement python binary research:

def binary_search(sorted_list, target, start, end):

  if start > end:

    return -1

  middle = (start + end) // 2

  if sorted_list[middle] == target:

    return middle

  elif sorted_list[middle] > target:

    return binary_search(sorted_list, target, start, middle – 1)


    return binary_search(sorted_list, target, middle + 1, end)

sorted_list = [1, 2, 3, 4, 5]

# Search for element 3

result = binary_search(sorted_list, 3, 0, len(sorted_list) – 1)

# Print the result

print(result)  # Output: 2

A performance and complexity analysis

Compared to linear search, which has a time complexity of O(n), binary search has a time complexity of O(log n), which means the time required to execute the algorithm increases with the size of the input list.

When the binary search is used, it can only be used on sorted lists. If a list isn’t sorted, it will need to be sorted first, adding O(n log n) time complexity.

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Advantages and Disadvantages of Binary Search

When compared to linear search, binary search offers the following advantages:

  • There is no comparison between linear search and binary search, especially for large lists.
  • It works only with binary search

The Use of Binary Search

If the list does not change frequently and sorting does not add too much cost, binary search is an efficient algorithm to find elements within a sorted list.

An overview of binary search limitations

It is important to note that binary search can only be used with sorted lists. If the list is not already sorted, then sorting must be factored in.

If the list is frequently updated or modified, the binary search may not be suitable, as the list must have resorted after every update. Instead, a balanced binary tree might be more appropriate.

Pitfalls and errors that commonly occur:

When implementing binary search in Python, you should be aware of the following errors and pitfalls:

  • Before performing the search, sort the list first. If the list is not sorted, the results will be inaccurate.
  • You should be careful not to exceed the bounds of the list when searching. Before accessing an element, make sure to check the list’s indices.
  • Recursion is based on the base case, so when the start index is greater than the end index, returns a value indicating that the element couldn’t be found.
  • Make sure to check for the presence of the element after using one of these functions to maintain the sorted order of the list.
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It has a time complexity of O(log n), which makes it more efficient than a linear search for finding elements within sorted lists. The binary search module and recursive functions in Python can be used to implement the binary search for large lists. Although this method has some limitations, it is a valuable tool for all programmers.