python binary search algorithm code example

Example 1: iterative binary search python

def binary_search(a, key):
	low = 0
	high = len(a) - 1
	while low < high:
		mid = (low + high) // 2
		if key == a[mid]:
			return True
		elif key < mid:
			high = mid - 1
		else:
			low = mid + 1

	return False

Example 2: binary search in python

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

Example 3: binary search python

# This is real binary search
# this algorithm works very good because it is recursive

def binarySearch(arr, min, max, x):
    if max >= min:
        i = int(min + (max - min) / 2) # average
        if arr[i] == x:
            return i
        elif arr[i] < x:
            return binarySearch(arr, i + 1, max, x)
        else:
            return binarySearch(arr, min, i - 1, x)

Example 4: code of binary search in python

def binary_search(mylist,low,k,key):
    high = k - 1
    mid = (low + high)//2
    
    if mylist[mid]==key:
        return mid
    elif key > mylist[mid]:
        return binary_search(mylist,mid + 1,k ,key)
    else:
        return binary_search(mylist,0,mid, key)
low = 0
k = int(input("Enter total amount of elements in k : "))
mylist = [int(input()) for x in range(k)]
key = int(input("Which element do  we have to find: "))
print(binary_search(mylist,low,k,key))