In this tutorial, we are going to write a program that returns a sublist element till nth sublist in a list. Let's say we have the following list with 5 sublists.
[['Python', 'Java'], ['C', 'Pascal'], ['Javascript', 'PHP'], ['C#', 'C++'], ['React', 'Angular']] Now, we have to get the first element from the first three sublists. We can get the elements different approaches. Let's see some of them.
Loops
More generic and first thought of the most of programmers is to use loops. Let's see the code using loops.
Example
# initializing the list and N random_list = [['Python', 'Java'], ['C', 'Pascal'], ['Javascript', 'PHP'], ['C# C++'], ['React', 'Angular']] N = 3 # empty list to store final elements from the sublists desired_elements = [] # iterating over the list till 3rd element for i in range(N): # storing the first element from the sublist desired_elements.append(random_list[i][0]) # printing the elements print(desired_elements)
Output
If you run the above code, then you will get the following result.
['Python', 'C', 'Javascript']
We can use the list comprehensions in place of for loop. Let's see the same code using list comprehensions.
Example
# initializing the list and N random_list = [['Python', 'Java'], ['C', 'Pascal'], ['Javascript', 'PHP'], ['C# C++'], ['React', 'Angular']] N = 3 # getting first element from the sublists desired_elements = [sublist[0] for sublist in random_list[:N]] # printing the elements print(desired_elements)
Output
If you run the above code, then you will get the following result.
['Python', 'C', 'Javascript']
Using Built-in Methods
Python provides a lot of built-in modules and methods. Let's use them to solve our problem.are going to use the map, itemgetter, and islice methods to achieve the output as expected.Let's see the code.
Example
# importing the required methods import operator # for itemgetter import itertools # for islice # initializing the list and N random_list = [['Python', 'Java'], ['C', 'Pascal'], ['Javascript', 'PHP'], ['C# C++'], ['React', 'Angular']] N = 3 # getting first element from the sublists desired_elements = list(map(operator.itemgetter(0), itertools.islice(random_list, N))) # printing the elements print(desired_elements)
Output
If you run the above code, then you will get the following result.
['Python', 'C', 'Javascript']
Conclusion
You can take any element in place of the first element. We have taken the first element for the demonstration. If you have any doubts in the tutorial, mention them in the comment section.