Python List append() Method with Examples - Scaler Topics (original) (raw)
Overview
The append() function in Python helps us add an element at the end of the list. It doesn't create a new list but modifies the existing one.
Syntax of append() Function in Python
The append function in Python has the following syntax:
The myList is the list where we want to add the element.
Parameters of append() Function in Python
It accepts a single element which could be any Python object
- integer, floating number, boolean, string, list, user-defined object etc.
This parameter is mandatory and can't be omitted. Leaving this parameter empty will give an error.
Return Value of append() Function in Python
Return Type: None
The append function doesn't return anything. It only modifies the original list.
Example of append() Function in Python
Here we will add elements like integers, floating numbers, and a string to a list.
Output
Explanation
- We created an original list that has some initial values in it.
- We then added an integer value at the end of the list.
- After that, we added a string followed by a floating value.
- Finally, we printed the original list and saw that all the new items get added to the list at the end in the same order.
What is append() Function in Python?
For example, if you have a list of overall toppers of the school, this list will always need to be updated every year to add new toppers at the end of the list. Ever wondered how you would update the list most easily? The answer to this problem is the Python append function, which adds an element at the end of the list.
The append() function of Python is used to add an item at the end of the list to which it is applied. The append function takes an element as a parameter to be added to the list.
The append function doesn't create a new list after adding the item, but it modifies the original list, i.e., it updates the same list by adding the item at its end.
Time Complexity for Append in Python
This function has constant time complexity i.e. O(1), because lists are randomly accessed so the last element can be reached in O(1) time that's why the time taken to add the new element at the end of the list is O(1).
Also, when a list is created in Python, it reserves 32 bits of the contiguous memory location. Whenever the combined size of elements of that list exceeds the memory space of the original list, it acquires the contiguous memory at another location of size double its previous size. In that scenario, the previous elements are copied to this new memory space, and new elements are appended to the list. So, this is considered as the worst case for appending any element to the list and the time complexity for this worst case is O(N) where N is the size of the original list.
More Examples
Example 1: Adding iterables to the existing list
Here, we will add iterables like lists, sets, or a dictionary to an existing list.
Output
Explanation
- We created an original list that has some initial values in it.
- We then added a list with different values at the end of the original list.
- After that, we added a set followed by a dictionary to the list.
- Finally, we printed the original list, and we saw that all the new items get added to the list at the end in the same order.
Example 2: Nested Lists
Here we are going to append a list2 into a list1 and then another list3 into the list2, let's see what will happen.
Output:
Explanation
- We created an original list1 which has some initial values in it.
- We then added a list2 with different values in it at the end of the original list1.
- After that, we added another list3 to the list2. As the list holds the address of the element, the changes will also appear in the list1.
- Finally, we printed the original list, and we saw that all the new items get added to the list2 and hence in the list1 at the end in the same order.
Click Here, to know more about nested lists in Python.
Conclusion
We talked about what's the append function in Python, then we saw how the append function is used in Python. After that, we explored the function in detail, along with examples.
Here are a few takeaways from the entire discussion.
- The append function doesn't modify the original list.
- It appends the element provided as a parameter to the end of the list.
- There is no Return Value.