Error in "BinarySearch String and integer Error"

Question

I want print call the binarySearch mehods inside the Util Class and want to return the index value along with string or number.

    class Utilily :
        @staticmethod
        def binarySearch(arr, l, r, key): # l = low, r = high
            if (r >= l):
                mid = int(l + (r - l)/2)
                if (arr[mid] == key):
                    return mid
                elif (arr[mid] > key):
                    return (binarySearch(arr,l,mid-1,key))
                 else:
                    return (binarySearch(arr,mid+1,r,key))
            else:
                return -1
    u = Utility()
    def main():
        n = int(input("Press \n 1. Binary Search Integer \n 2. Binary Search String \n 3. Exit \n"))
       if n == 1:
            n = int(input("Enter the Number of elements you want to insert:"))
            arr = list()
            print("Enter the elements:")
            for i in range(n):
                arr.append(int(input()))
            key = int(input("Enter the Key element:"))
            result = u.binarySearch(arr, 0, len(arr)-1, key)
            if (result != -1):
                print("Element is present at index %d" % result)
            else:
                print("Element is not present in array")
        elif n == 2:
            n = int(input("Enter the Number of elements you want to insert:"))
            arr = list()
            print("Enter the elements in assending order: (i.e from A-Z)")
            for i in range(n):
                    arr.append(input())
            key = input("Enter the Key element:")
            result = u.binarySearch(arr, 0, len(arr)-1, key)
            #print(result)
            if (result != -1):
                    print("Element is present at index %d" % result)
            else:
                    print("Element is not present in array")
        elif n == 3:
            exit()

' Error for Integer

Press 
 1. Binary Search Integer 
 2. Binary Search String 
 3. Exit  1 Enter the Number of elements you want to insert:5 Enter the elements: 1 2 3 4 5 Enter the Key element:5 Traceback (most recent
call last):   File "my.py", line 47, in 
    main()   File "my.py", line 26, in main
    result = u.binarySearch(arr, 0, len(arr)-1, key)   File "my.py", line 11, in binarySearch
    return (binarySearch(arr,mid+1,r,key)) NameError: name 'binarySearch' is not defined


But I need an out put of "index 4" 

Error for String

 Press 
 1. Binary Search Integer 
 2. Binary Search String 
 3. Exit  2 Enter the Number of elements you want to insert:5 Enter the elements in assending order: (i.e from A-Z) a b c d e Enter the
Key element:e Traceback (most recent call last):   File "my.py", line
47, in 
    main()   File "my.py", line 38, in main
    result = u.binarySearch(arr, 0, len(arr)-1, key)   File "my.py", line 11, in binarySearch
    return (binarySearch(arr,mid+1,r,key)) NameError: name 'binarySearch' is not defined 

Can Anyone Help me out? Please..... '

Answer 1

Change :

return (binarySearch(arr,l,mid-1,key))

To :

return (Utility.binarySearch(arr,l,mid-1,key))

And change:

return (binarySearch(arr,mid+1,r,key))

To:

return (Utility.binarySearch(arr,mid+1,r,key))

Why? Because binarySearch is a method declared inside the Utility class and not a global function.