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

// C++ program to implement recursive Binary Search 
#include <bits/stdc++.h> 
using namespace std; 
  
// A recursive binary search function. It returns 
// location of x in given array arr[l..r] is present, 
// otherwise -1 
int binarySearch(int arr[], int l, int r, int x) 
{ 
    if (r >= l) { 
        int mid = l + (r - l) / 2; 
  
        // If the element is present at the middle 
        // itself 
        if (arr[mid] == x) 
            return mid; 
  
        // If element is smaller than mid, then 
        // it can only be present in left subarray 
        if (arr[mid] > x) 
            return binarySearch(arr, l, mid - 1, x); 
  
        // Else the element can only be present 
        // in right subarray 
        return binarySearch(arr, mid + 1, r, x); 
    } 
  
    // We reach here when element is not 
    // present in array 
    return -1; 
} 
  
int main(void) 
{ 
    int arr[] = { 2, 3, 4, 10, 40 }; 
    int x = 10; 
    int n = sizeof(arr) / sizeof(arr[0]); 
    int result = binarySearch(arr, 0, n - 1, x); 
    (result == -1) ? cout << "Element is not present in array"
                   : cout << "Element is present at index " << result; 
    return 0; 
} 

# Iterative Binary Search Function 
# It returns index of x in given array arr if present, 
# else returns -1 
def binary_search(arr, x): 
    low = 0
    high = len(arr) - 1
    mid = 0
  
    while low <= high: 
  
        mid = (high + low) // 2
  
        # Check if x is present at mid 
        if arr[mid] < x: 
            low = mid + 1
  
        # If x is greater, ignore left half 
        elif arr[mid] > x: 
            high = mid - 1
  
        # If x is smaller, ignore right half 
        else: 
            return mid 
  
    # If we reach here, then the element was not present 
    return -1
  
  
# Test array 
arr = [ 2, 3, 4, 10, 40 ] 
x = 10
  
# Function call 
result = binary_search(arr, x) 

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

# Python 3 program for recursive binary search. 
# Modifications needed for the older Python 2 are found in comments. 
  
# Returns index of x in arr if present, else -1 
def binary_search(arr, low, high, x): 
  
    # Check base case 
    if high >= low: 
  
        mid = (high + low) // 2
  
        # If element is present at the middle itself 
        if arr[mid] == x: 
            return mid 
  
        # If element is smaller than mid, then it can only 
        # be present in left subarray 
        elif arr[mid] > x: 
            return binary_search(arr, low, mid - 1, x) 
  
        # Else the element can only be present in right subarray 
        else: 
            return binary_search(arr, mid + 1, high, x) 
  
    else: 
        # Element is not present in the array 
        return -1
  
# Test array 
arr = [ 2, 3, 4, 10, 40 ] 
x = 10
  
# Function call 
result = binary_search(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") 

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)

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")

def binary_search(group, suspect):
  group.sort()
  midpoint = len(group)//2
  while(True):
    if(group[midpoint] == suspect):
      return midpoint
    if(suspect > group[midpoint]):
            group = group[midpoint]
    if(suspect < group[midpoint]):
      group = group[0: midpoint]
    midpoint = (len(group)//2)