Python Lists Methods
In this lesson, we’ll discuss Python lists methods with examples in order to achieve our instructional goals.
- Python Lists Methods:
- Lists/Array Methods In Python:
- Python List append() Method:
- Python List clear() Method:
- Python List copy() Method:
- Python Lists Methods count():
- Python Lists Methods extend():
- Python Lists Methods index():
- Python Lists Methods insert():
- Python Lists Methods pop():
- Python Lists Methods remove():
- Python Lists Methods reverse():
- Python Lists Methods sort():
- Python Lists Methods Importance:
Lists/Array Methods In Python
There are several built-in Python lists methods that you can use when dealing with Python lists or Array.
Here, you will discover the entire assortment of methods for working with Python lists/arrays, complete with examples.
|append()||The element is added at the end of the list.|
|clear()||Deletes all elements from the list.|
|copy()||Provides a copy of the list as a result.|
|count()||Provides a count of elements with a specified value.|
|extend()||You can add elements to the current list (or any iterable) by adding them to the end of the list.|
|index()||This method returns the index of the first element with the provided value.|
|insert()||The element is added at the position given.|
|pop()||The element at the given position is removed.|
|remove()||Delete the item with the given value.|
|reverse()||Sorts the list in reverse order.|
|sort()||Organize the list.|
Python List append() Method
In Python list, the append() method is apply to declare an item at the end of the list.
Necessary. Any type of element (string, number, object, etc.)
A new item should be added to the companies list:
To incorporate a new list of companies to an existing one, simply append the new list to the current one:
Python List clear() Method
The clear() method in Python eliminates all of the items from a list.
Clear all items from the firms list.
Now attempt to combine 2 lists and then delete all items from the list:
As demonstrated in the example above, the first print will feature the list item, while the second print will show an empty list.
Python List copy() Method
The copy() method in Python returns a replica of the designated list.
Duplicate the firms list:
Now duplicate both old firms and newfirms list items in a single list:
Python Lists Methods: count()
The python count() method furnishes the amount of elements with a designated value.
|value||Any data type (character string, numerical value, list, tuple, etc.). The element to look for.|
Determine how many times the name “Google” appears in the list of firms:
Here is another example:
Python Lists Methods: extend()
The extend() method of python appends the certain list items (or any iterable) to the end of the existing list.
|iterable||Necessary. Any iterable (such as lists, sets, tuples, etc.)|
Place the companies’ items in the newfirms list:
Now add three list items in a single list:
Python Lists Methods: index()
When the index() method is called, it returns the position where the given value first occurs.
|elmnt||This is necessary. A string, a number, a list, etc. Search for this element.|
Here are the positions of the index value “Google”:
You will only get the first occurrence of the value with the index() method.
Combine the two lists/arrays and find the position of “Alphabet Inc”:
Python Lists Methods: insert()
When insert() is called, the given value is inserted at the chosen position.
|pos||It is necessary. The position in which the value should be inserted|
|elmnt||This is essential. Any type of element (string, number, object, etc.).|
In the firms list, add “wallmart” as the fift element:
The next step is to add the value “IBM” at the end of the list of firms and extend it with newfirms list:
Python Lists Methods: pop()
Using pop(), you can remove an element from a particular position.
|pos||It is optional. Specifies the place where the element should be removed, default value is -1, which returns the last item|
From the frms list, remove the fourth element:
The removed element should be returned from the firms list/array as follows:
Python Lists Methods: remove()
When Python remove() method is called, it removes the first occurrence of the element with the specified value.
|elmnt||This is required. You can remove any type of element (string, number, list, etc.)|
Remove the “Meta” element of the firms list:
Take both lists/arrays and merge them. Remove the last element from the merged list:
Python Lists Methods: reverse()
With Python’s reverse() method, the elements are sorted in reverse order.
List the firms in reverse order:
Then, merge the two Python lists/arrays and print them in reverse order:
Python Lists Methods: sort()
Lists are sorted ascending by default with the sort() method.
If you want to decide what sorting criteria should be used, you can also write a function.
|reverse||When reverse=True, the list will be sorted descending. Reverse is set to False by default – This is optional.|
|key||Optional function for specifying sorting criteria.|
The firms list should be sorted alphabetically as follows:
List the firms in descending order:
The list of firms should now be sorted by their length:
Note that by default length, lists elements are displayed from smaller to bigger characters.
Now sort the firms list by their characters’ length in reverse order:
The firms’ lists/arrays should now be merged and sorted by the length of their characters in default order:
Python Lists Methods Importance
Here are some key reasons highlighting the importance of Python list methods:
- List methods such as
pop()allow for dynamic modification of list contents. These methods enable you to add elements to the list, remove specific elements, insert elements at specific positions, and retrieve and remove elements from the list based on their indices. These operations are fundamental for maintaining and updating list data.
- List methods like
count()provide convenient ways to search for elements within a list. The
index()method returns the index of the first occurrence of a specified element, enabling quick access to the desired data. The
count()method counts the number of occurrences of a given element within the list, aiding in data analysis and statistics.
sort()method allows you to sort the elements of a list in-place, either in ascending or descending order. Sorting lists is crucial for various applications, including data organization, efficient search, and algorithmic implementations. Additionally, the
reverse()method reverses the order of elements in a list, providing a quick way to change the sequence of data.
copy()method creates a shallow copy of a list, allowing you to create an independent copy of the original list. This is important when you need to modify one list while preserving the integrity of the other. The
copy()method prevents unintended side effects that can occur when multiple variables refer to the same list object.
- List slicing, facilitated by the use of indexing and slicing notation, allows you to extract specific portions of a list. Slicing is useful for operations such as extracting subsets of data, manipulating specific ranges of elements, or creating new lists based on certain criteria. It provides a flexible and efficient way to work with different parts of a list.