Summary: Use given_string.rsplit('sep', 1)[-1] to split the string and get the last element. Another approach is to use given_string.rpartition('sep', 1)[-1]
Minimal Solution:
dob = '21/08/2023'
# Method 1
print(dob.rsplit('/', 1)[-1])
# Method 2
print(dob.rpartition('/')[-1]) # OUTPUT: 2023
Problem Formulation
Problem: Given a string. How will you split the string and get the last element?
Let’s try to understand the given problem with the help of an example:
Example 1
# Input:
text = 'Java_C++_C#_Golang_Python'
# Expected Output:
Split String: ['Java_C++_C#_Golang', 'Python']
Last Element: Python
In the above example, “_” is the separator. However, not the entire string has been split. Only the last substring that comes after the separator has been extracted.
Example 2
# Input:
text = 'Java_C++_C#_Golang_Python_'
# Expected Output:
Split String: ['Java_C++_C#_Golang', 'Python']
Last Element: Python
Unlike the previous example, the input string ends with the separator itself. However, the output is similar. So, you have a different input string, but you have to generate a similar output by eliminating the separator.
Let’s dive into the different ways of solving the given problems.
Method 1: Using rsplit
Prerequisite: Simply put, the rsplit method splits a given string based on a given separator and stores the characters/substrings into a list. For example, finxterx42'.rsplit('x') will return the list ['fin', 'ter', '42'] as an output. rsplit can take two arguments –
sep– The separator string on which it is split.maxsplit– The number of times the string is split.
Thus, you can use the maxsplit argument to your advantage and solve the given question by setting maxsplit = 1. This means the string will be split along the specified separator only once from the right end. Once the string is split into two parts from the right end, all that you need to do is extract the second element from the list created by the rsplit method.
Solution to Example 1:
text = 'Java_C++_C#_Golang_Python'
print("Split String: ", text.rsplit('_', 1))
print("Last Element: ", text.rsplit('_', 1)[-1])
Output:
Split String: ['Java_C++_C#_Golang', 'Python']
Last Element: Python
Solution to Example 2: In the second scenario, you must get rid of the separator that comes at the end of the string. Otherwise, simply using rsplit with the maxsplit argument will create a list that will create a list that will contain an empty character as the last item as shown below –
To avoid this problem, you can use the strip() function to get rid of the separator and then use rsplit as shown in the snippet below.
text = 'Java_C++_C#_Golang_Python_'
text = text.strip('_')
print("Split String: ", text.rsplit('_', 1))
print("Last Element: ", text.rsplit('_', 1)[-1])
Output:
Split String: ['Java_C++_C#_Golang', 'Python'] Last Element: Python
Method 2: Using rpartition
You can also use the rpartition method to solve the given problem. The rpartition method searches for a separator substring and returns a tuple with three strings: (1) everything before the separator, (2) the separator itself, and (3) everything after it. For example: finxterx42'.rpartition('x') will return the following tuple: ('finxter', 'x', '42')
Thus, you can simply extract the last item from the tuple after the string has been cut by the rpartition method.
Code:
# Solution to Example 1
text = 'Java_C++_C#_Golang_Python'
print("Split String: ", text.rpartition('_'))
print("Last Element: ", text.rpartition('_')[-1]) # Solution to Example 2
text = 'Java_C++_C#_Golang_Python_'
text = text.strip('_')
print("Split String: ", text.rpartition('_'))
print("Last Element: ", text.rpartition('_')[-1])
Output:
Split String: ('Java_C++_C#_Golang', '_', 'Python')
Last Element: Python
Coding Challenge
Before we wrap up this tutorial, here’s a coding challenge for you to test your grip on the concept you just learned.
| Input: Consider the following IP Address – ip = 110.210.130.140 Challenge: Extract the network bit from the given class A ip address and convert it to its binary form. Expected Output: 10001100  Hint:– 140 is the network bit! – How to Convert a String to Binary in Python? |
Solution:
ip = '110.210.130.140'
nw_bit = int(ip.rpartition('.')[-1])
print(bin(nw_bit)[2:])
Explanation: The solution is pretty straightforward. You first have to extract the network bit, i.e., 140. This happens to be the last item after the “.“. So, you can use rpartition and feed “.” as the separator and extract the last item (the network bit) from the tuple returned by the rpartition method. Since this will be a string, you must convert it to an integer and then typecast this integer to a binary number using the bin function to generate the final output.
Related Read: Python Print Binary Without ‘0b’
Conclusion
I hope you enjoyed the numerous scenarios and challenges used in this tutorial to help you learn the two different ways of splitting a string and getting the last item. Please subscribe and stay tuned for more interesting tutorials and solutions.
Recommended Reads:
⦿ How To Split A String And Keep The Separators?
⦿ How To Cut A String In Python?
⦿ Python | Split String into Characters
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