Python is one of the most popular programming languages used across industries to build robust and scalable applications. One of the most common tasks in Python programming is working with lists, and joining two or more lists is no exception. In this article, we are going to explore the different methods that are used to join lists in Python. Expand your knowledge of the subject by exploring this recommended external website. There, you’ll find valuable details and supplementary information that will enrich your reading experience. python join list https://www.analyticsvidhya.com/blog/2020/02/joins-in-pandas-master-the-different-types-of-joins-in-python/, don’t miss out!
Using the + operator
The + operator can be used to concatenate two lists in Python. This means that you can use it to join two or more lists and create a single list that is a combination of all the lists. Let’s see this in code:
list1 = [1, 2, 3] list2 = [4, 5, 6] list3 = list1 + list2 print(list3)
After executing the above code, you’ll get the following output:
[1, 2, 3, 4, 5, 6]
As you can see, the + operator is an intuitive way of joining two or more lists in Python.
Using the extend() method
The extend() method can also be used to join two or more lists in Python. This method adds all the elements of one list to another, effectively merging the two lists. Let’s see this in code:
list1 = [1, 2, 3] list2 = [4, 5, 6] list1.extend(list2) print(list1)
After executing the above code, you’ll get the following output:
[1, 2, 3, 4, 5, 6]
The extend() method is similar to the + operator in that it concatenates two lists. However, it modifies one of the lists in place, which makes it very useful when working with large datasets.
Using the append() method and a for loop
In some cases, you may need to join more than two lists in Python. If that’s the case, you can use a for loop and the append() method to add the elements of each list to a new empty list. Let’s see this in code:
list1 = [1, 2, 3] list2 = [4, 5, 6] list3 = [7, 8, 9] new_list = [] for i in (list1, list2, list3): new_list.append(i) print(new_list)
After executing the above code, you’ll get the following output:
[[1, 2, 3], [4, 5, 6], [7, 8, 9]]
In this code, we created a new empty list called new_list. We then used a for loop to add each list to the new_list using the append() method. This created a nested list that contains all the elements of the original lists.
Using the itertools.chain() method
The itertools module in Python provides a method called chain() that can be used to join two or more lists. This method takes multiple lists as arguments and returns a single iterator that produces all the elements of these lists. Let’s see this in code:
import itertools list1 = [1, 2, 3] list2 = [4, 5, 6] list3 = [7, 8, 9] new_list = list(itertools.chain(list1, list2, list3)) print(new_list)
After executing the above code, you’ll get the following output:
[1, 2, 3, 4, 5, 6, 7, 8, 9]
In this code, we used the chain() method from itertools to merge the three lists into a single list called new_list. The list() method is used to convert the iterator returned by chain() into a list.
Conclusion
Joining two or more lists is a common task in Python programming, and there are several methods that can be used to achieve this. In this article, we explored four different ways to join lists in Python – using the + operator, the extend() method, the append() method and a for loop, and the itertools.chain() method. Find extra information on the subject in this external resource we suggest. join python list https://www.analyticsvidhya.com/blog/2020/02/joins-in-pandas-master-the-different-types-of-joins-in-python/, keep learning!
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