Why use Lists?
Sometimes, there may be situations where you need to handle different types of data at the same time. For example, let’s say, you need to have a string type element, an integer and a floating-point number in the same collection. Now, this is fairly impossible with the default data types that are available in other programming languages like C & C++. In simple words, if you define an array of type integer, you can only store integers in it. This is where Python has an advantage. With its list collection data type, we can store elements of different data types as a single ordered collection!
Now that you know how important lists are, let’s move on to see what exactly are Lists and how to remove elements from list!
Methods:
Many methods exist in Python to modify the list. Some common methods to add and remove data in the list are mentioned here.
insert [index,item]: This method is used to insert any item in the particular index of the list and right shift the list items.
append [item]: This method is used to add new element at the end of the list.
extend [anotherList]: The items of one list can be inserted at the end of another list by using this method.
remove [item]: This method is used to remove particular item from the list.
pop [index]: The method is used to remove item from the list based on index value.
del[]: This method is used to remove the particular item of the list or slice the list.
clear[]: This method is used to remove all items of a list
Add items into the list:
Different ways to add items in Python list are shown in this part of the tutorial.
Example 1: Insert item using insert[] method
Create a python file with the following script to see the use of insert[] method. A new item will be inserted in the third position of the list and the other items will be shifted right after running the script.
listdata = [89, 56, 90, 34, 89, 12]
# Insert data in the 2nd position
listdata.insert[2, 23]
# Displaying list after inserting
print["The list elements are"]
for i in range[0, len[listdata]]:
print[listdata[i]]
Output:
The following output will appear after running the script.
Example 2: Insert item using append[] method
Create a python file with the following script to see the use of append[] method. It is mentioned before that append[] method inserts data at the end of the list. So, ‘Toshiba’ will be inserted at the end of listdata after running the script.
listdata = ["Dell", "HP", "Leveno", "Asus"]
# Insert data using append method
listdata.append["Toshiba"]
# Display the list after insert
print["The list elements are"]
for i in range[0, len[listdata]]:
print[listdata[i]]
Output:
The following output will appear after running the script.
Example 3: Insert item using extend[] method
Create a python file with the following script to see the use of extend[] method. Here, two lists are declared in the script which are combined together by using extend[] method. The items of the second list will be added at the end of the first list.
list1 = ['html', 'CSS', 'JavaScript', 'JQuery']
# initializing the second list
list2 = ['PHP', 'Laravel', 'CodeIgniter']
# Combine both lists using extend[] method
list1.extend[list2]
# Display the list after combing
print ["The list elements are :"]
for i in range[0, len[list1]]:
print[list1[i]]
Output:
The following output will appear after running the script.
How to insert and remove elements from a list in Python
Lists are mutable, meaning that elements of lists can be changed once they have been assigned to variables. We can change an element in a list, we can delete an entire list, and we can add and remove one element from a list after assigning it to a variable.
Remove an element from List by value using list.remove[]
Python’s list provides a member function to remove an element from list i.e.
It removes the first occurrence of given element from the list.
For example,
Suppose we have a list of numbers i.e.
Let’s remove 56 from the given list using list.remove[] i.e.
# Remove first occurrence of 56 from List listOfnum.remove[56]
It will remove the first occurrence of 56 from the above lists. Lists contents will be now,
[12, 44, 45, 34, 3, 56, 4, 33, 44, 56]
If we try to remove the element that doesn’t exists in list then list.remove[] will throw exception.
Therefore before calling list.remove[] we should either,
Check if element exists in list i.e.
Or use try / except i.e.
# If given element doesn't exists in list, then remove[] can throw Error # Therefore use try / except while calling list.remove[] try : listOfnum.remove[99] except ValueError: print["Given Element Not Found in List"]
Related Articles
- Python: Remove elements from a list while iterating
- Python: Remove elements from list by value [first or all occurrences]
- Python: Remove elements from list by index or indices
Remove an item from a list in Python [clear, pop, remove, del]
In Python, use list methods clear[], pop[], and remove[] to remove items [elements] from a list. It is also possible to delete items using del statement by specifying a position or range with an index or slice.
- Remove all items: clear[]
- Remove an item by index and get its value: pop[]
- Remove an item by value: remove[]
- Remove items by index or slice: del
- Remove items that meet the condition: List comprehensions
See the following article for adding items to the list.
- Add an item to a list in Python [append, extend, insert]
Python List Remove: How to Delete an Element From List
In Python, Integer or float objects, for example, are primitive data types that can’t be further mutilated. Furthermore, these data types are immutable, meaning that they can’t be modified once they have been assigned. Thus, it doesn’t make any sense to think of changing the value of an integer.
Lists are defined by enclosing a comma-separated series of items in square brackets [[ ]],
If you need a different integer, then you assign a different one. No need to modify the existing one.