Python – Access element at Kth index in given String

Given a String, access element at Kth index.

Input : test_str = ‘geeksforgeeks’, K = 4 Output : s Explanation : s is 4th element Input : test_str = ‘geeksforgeeks’, K = 24 Output : string index out of range Explanation : Exception as K > string length.

Method #1 : Using [] operator 

This is basic way in which this task is performed. In this, we just enclose Kth index in square brackets. If K can be greater then length of string, its recommended to enclose in try-except block.

Python3

# Python3 code to demonstrate working of
# Access element at Kth index in String
# Using []

# initializing string
test_str = 'geeksforgeeks'

# printing original string
print("The original string is : " + str(test_str))

# initializing K
K = 7

# try-except block for error handling
try :

    # access Kth element
    res = test_str[K]
except Exception as e :
    res = str(e)

# printing result
print("Kth index element : " + str(res))

Output

The original string is : geeksforgeeks
Kth index element : r

Method #2 : Using Negative index + len() + [] operator

This is yet another way in which this task can be performed. In this, we compute length of string and subtract K from it, it results in Kth index from beginning, and negative indexed.

Python3

# Python3 code to demonstrate working of
# Access element at Kth index in String
# Using Negative index + len() + [] operator

# initializing string
test_str = 'geeksforgeeks'

# printing original string
print("The original string is : " + str(test_str))

# initializing K
K = 7

# try-except block for error handling
try :

    # access Kth element
    # using negative index
    res = test_str[-(len(test_str) - K)]
except Exception as e :
    res = str(e)

# printing result
print("Kth index element : " + str(res))

Output

The original string is : geeksforgeeks
Kth index element : r

The Time and Space Complexity for all the methods are the same

Time Complexity: O(1) -> Accessing an element in a list takes O(1), hence average time complexity of code is O(1)

Space Complexity: O(1)