how to make a binary search algorithm in python code example
Example 1: 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 2: recursive binary search python
def binary_search_recursive(A, key, low, high):
if low > high:
return False
else:
mid = (low + high) // 2
if key == A[mid]:
return True
elif key < A[mid]:
return binary_search_recursive(A, key, low, mid - 1)
else:
return binary_search_recursive(A, key, mid + 1, high)
Example 3: binary search algorithm in python code
def binarySearchAppr (arr, start, end, x):
# check condition
if end >= start:
mid = start + (end- start)//2
# If element is present at the middle
if arr[mid] == x:
return mid
# If element is smaller than mid
elif arr[mid] > x:
return binarySearchAppr(arr, start, mid-1, x)
# Else the element greator than mid
else:
return binarySearchAppr(arr, mid+1, end, x)
else:
# Element is not found in the array
return -1
arr = sorted(['t','u','t','o','r','i','a','l'])
x ='r'
result = binarySearchAppr(arr, 0, len(arr)-1, x)
if result != -1:
print ("Element is present at index "+str(result))
else:
print ("Element is not present in array")