Python: Binary search

Last update on August 19 2022 21:50:47 (UTC/GMT +8 hours)

Python Search and Sorting : Exercise-1 with Solution

Write a Python program for binary search.
Binary Search : In computer science, a binary search or half-interval search algorithm finds the position of a target value within a sorted array. The binary search algorithm can be classified as a dichotomies divide-and-conquer search algorithm and executes in logarithmic time.

Step by step example :

Sample Solution:

Python Code:

def binary_search(item_list,item):
	first = 0
	last = len(item_list)-1
	found = False
	while( first<=last and not found):
		mid = (first + last)//2
		if item_list[mid] == item :
			found = True
		else:
			if item < item_list[mid]:
				last = mid - 1
			else:
				first = mid + 1	
	return found
	
print(binary_search([1,2,3,5,8], 6))
print(binary_search([1,2,3,5,8], 5))

Sample Output:

False                                                                                                         
True

Flowchart:

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Python: Tips of the Day

Enum Class:

Here is another classy approach from Python, no pun intended. Python's enum class will let you create enum object members with constant and unique values which then can be listed, compared or used for identification.

Enum classes are also iterable so they can be iterated as well:

from enum import Enum
class sports(Enum):
    volleyball = 1
    soccer = 2
    running = 3
    football = 4
    baseball = 5
    boxing = 6
print(sports.baseball)
print(repr(sports.baseball))

Output:

sports.baseball
<sports.baseball: 5>