Appending To One List In A List Of Lists
Last Updated :
30 Apr, 2024
in a list in Python can be achieved using various methods, each with its own advantages. Choose the approach that best fits your specific requirements Lists of lists, also known as nested lists, are a powerful data structure in programming that allow for the organization of data in a hierarchical manner. In this article, we will explore some simple and commonly used methods for appending to one list in a list of lists using Python as our programming language.
Appending To One List In A List Of Lists
Below, are the methods of Appending To One List In A List Of Lists in Python.
Appending To One List In A List Of Lists Using Indexing
The most straightforward method to append an element to a specific sublist is to use indexing along with the append
method. Here’s an example: This method is simple and direct, but it requires knowing the index of the sublist you want to modify.
Python3
list_of_lists = [[ 1 , 2 , 3 ], [ 4 , 5 , 6 ], [ 7 , 8 , 9 ]]
sublist_to_append_to = list_of_lists[ 1 ]
sublist_to_append_to.append( 10 )
print (list_of_lists)
|
Output
[[1, 2, 3], [4, 5, 6, 10], [7, 8, 9]]
Appending To One List In A List Of Lists Using List Comprehension
List comprehension is a concise and elegant way to achieve the same result. It allows you to create a new list by applying an expression to each item in an existing list. Here’s an example: This method creates a new list by concatenating the existing sublist with the new element.
Python3
list_of_lists = [[ 1 , 2 , 3 ], [ 4 , 5 , 6 ], [ 7 , 8 , 9 ]]
index_to_append_to = 1
list_of_lists[index_to_append_to] = [item for item in list_of_lists[index_to_append_to]] + [ 10 ]
print (list_of_lists)
|
Output
[[1, 2, 3], [4, 5, 6, 10], [7, 8, 9]]
Appending To One List In A List Of Lists Using Extend Method
The extend
method can be used to append multiple elements to a list. When applied to a sublist, it can be an efficient way to add a single element. Here’s an example: The extend
method is originally designed for adding multiple elements, so using it for a single element might be considered less conventional.
Python3
list_of_lists = [[ 1 , 2 , 3 ], [ 4 , 5 , 6 ], [ 7 , 8 , 9 ]]
index_to_append_to = 1
list_of_lists[index_to_append_to].extend([ 10 ])
print (list_of_lists)
|
Output
[[1, 2, 3], [4, 5, 6, 10], [7, 8, 9]]
Appending To One List In A List Of Lists Using Insert Method
The insert
method allows you to insert an element at a specified position in a list. This method can be used to append an element to a specific sublist by specifying the desired index. Here’s an example: While effective, the insert
method might be less intuitive for appending to the end of a list.
Python3
list_of_lists = [[ 1 , 2 , 3 ], [ 4 , 5 , 6 ], [ 7 , 8 , 9 ]]
index_to_append_to = 1
list_of_lists[index_to_append_to].insert( len (list_of_lists[index_to_append_to]), 10 )
print (list_of_lists)
|
Output
[[1, 2, 3], [4, 5, 6, 10], [7, 8, 9]]
Conclusion
In conclusion, appending to one list in a list of lists can be achieved through various methods in Python. The choice of method may depend on factors such as readability, performance, and personal preference. Understanding these techniques can empower you to work efficiently with nested lists in your programming endeavors
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