Given a string and an integer N, the task is to write a Python program to print the last N characters of the string.
Example
Input: Geeks For Geeks!; N = 4
Output: eks!
Explanation: The given string is Geeks For Geeks! and the last 4 characters is eks!.
Input: PYTHON; N=1
Output: N
Explanation: The given string is PYTHON and the last character is N.
Get the last N Characters of a String
Below are the lists of methods that we will cover in this article:
- Using a Python loop
- Using List slicing
- Using string slicing with negative indexing
- Using Recursion in Python
Using a loop to get the last N characters of a string
Using a loop to get to the last n characters of the given string by iterating over the last n characters and printing them one by one.
Python3
# get inputStr = "Geeks For Geeks!"N = 4# print the stringprint(Str)# iterate loopwhile(N > 0): # print character print(Str[-N], end='') # decrement the value of N N = N-1 |
Output
Geeks For Geeks!
eks!
Get the last N characters of a string using Slicing
Python list slicing is used to print the last n characters of the given string.
Using string slicing with positive indexing
Here we are using the concept of positive slicing where we are subtracting the length with n i.e. to get the positive index for the desired substring.
Python
# get inputStr = "Geeks For Geeks!"N = 4# print the stringprint(Str)# get length of stringlength = len(Str)# create a new string of last N charactersStr2 = Str[length - N:]# print Last N charactersprint(Str2) |
Output:
Geeks For Geeks!
eks!
Using string slicing with negative indexing
Here we are using the concept of negative slicing where we are not subtracting the length with n.
Python3
# get inputStr = "Geeks For Geeks!"N = 4# print the stringprint(Str)# create a new string of last N charactersStr2 = Str[-N:]# print Last N charactersprint(Str2) |
Output:
Geeks For Geeks!
eks!
Get the last characters of a string in Python
In Python, negative indexing allows you to access elements from the end of a sequence. So Str[-1] will give you the last character of the string.
Python3
Str = "Lazyroar"#using negative index to pick the last element of the string# Here -1 refers to the last character index in the stringlast_character = Str[-1]#printing the last characterprint(last_character) |
Output:
s
# Time Complexity: O(1)
# Auxiliary Space: O(1)
Get the Last N Characters of a String Using Recursion
Here we use a recursive function that progressively reduces the length of the string in recursion to get desired last N character that we won’t get
Python3
# get inputStr = "Geeks For Geeks!"N = 4 # print the stringprint(Str)def printLastNChar(Str, N): l = len(Str) if N > 0: print(Str[l - N], end = "") printLastNChar(Str, N - 1)printLastNChar(Str, N) |
Geeks For Geeks! eks!
# Time Complexity: O(n)
# Auxiliary Space: O(n)
Get Last N Characters of a String Using Operator.getitem():
Used operator.getitem(), slice() to extract the sliced string from length-N to length and assigned it to Str2 variable then displayed the Str2 variable.
Python3
# get inputStr = "Geeks For Geeks!"N = 4# print the stringprint(Str)# get length of stringlength = len(Str)import operator# create a new string of last N charactersStr2 = operator.getitem(Str, slice(length-N, length))# print Last N charactersprint(Str2) |
Geeks For Geeks! eks!
# Time Complexity: O(n)
# Auxiliary Space: O(n)
Get the Last N Characters of a String Using the Partition and str[-N:] methods:
Split the string into 3 parts using the partition method and then print the result
Python3
# get inputStr = "Geeks For Geeks!"N = 4# print the stringprint(Str)# split the string into 3 partsfirst, last_N, _ = Str.partition(Str[-N:])# print the resultprint(last_N) |
Geeks For Geeks! eks!
Time complexity: O(N), where N is the length of the substring to be reversed.
Auxiliary space: O(N), since we create a list of N characters to store the reversed substring.
