{"id":79,"date":"2020-10-03T01:15:48","date_gmt":"2020-10-03T01:15:48","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=79"},"modified":"2025-03-26T13:43:08","modified_gmt":"2025-03-26T13:43:08","slug":"python-list","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/python-basics\/python-list\/","title":{"rendered":"Python List"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about Python List type and how to manipulate list elements effectively.<\/p>\n\n\n\n

What is a List #<\/a><\/h2>\n\n\n\n

A list is an ordered collection of items. <\/p>\n\n\n\n

Python uses the square brackets ([]<\/code>) to indicate a list. The following shows an empty list:<\/p>\n\n\n

empty_list = []<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Typically, a list contains one or more items. To separate two items, you use a comma (,). For example:<\/p>\n\n\n
todo_list = ['Learn Python List'<\/span>,'How to manage List elements'<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
\"Python<\/figure>\n\n\n\n
Since a list often contains many items, it’s a good practice to name it using plural nouns e.g., numbers<\/code>, colors<\/code>, and shopping_carts<\/code>.<\/p>\n\n\n\n
The following example defines a list of six numbers<\/a>:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
If you print out the list, you’ll see its representation including the square brackets. For example:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
[1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
\"\"<\/figure>\n\n\n\n
The following shows how to define a list of strings<\/a>:<\/p>\n\n\n
colors = ['red'<\/span>, 'green'<\/span>, 'blue'<\/span>]\nprint(colors)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
['red'<\/span>, 'green'<\/span>, 'blue'<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
\"\"<\/figure>\n\n\n\n
A list can contain other lists. The following example defines a list of lists:<\/p>\n\n\n
coordinates = [[0<\/span>, 0<\/span>], [100<\/span>, 100<\/span>], [200<\/span>, 200<\/span>]]\nprint(coordinates)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n
[[0<\/span>, 0<\/span>], [100<\/span>, 100<\/span>], [200<\/span>, 200<\/span>]]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Accessing elements in a list #<\/a><\/h2>\n\n\n\n
Since a list is an ordered collection, you can access its elements by indexes like this:<\/p>\n\n\n
list[index]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Lists are zero-based indexes. In other words, the first element has an index of 0, the second element has an index of 1, and so on.<\/p>\n\n\n\n
For example, the following shows how to access the first element of the numbers<\/code> list:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nprint(numbers[0<\/span>])<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
1<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The numbers[1]<\/code> will return the second element from the list:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nprint(numbers[1<\/span>])<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
3<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The negative index allows you to access elements starting from the end of the list. <\/p>\n\n\n\n
The list[-1]<\/code> returns the last element. The list[-2]<\/code> returns the second last element, and so on. For example:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nprint(numbers[-1<\/span>])\nprint(numbers[-2<\/span>])<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
4<\/span>\n9<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Modifying, adding, and removing elements #<\/a><\/h2>\n\n\n\n
A list is dynamic. It means that you can modify elements in the list, add new elements to the list, and remove elements from a list.<\/p>\n\n\n\n
Modifying elements in a list #<\/a><\/h3>\n\n\n\n
To change an element, you assign a new value to it using this syntax:<\/p>\n\n\n
list[index] = new_value<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The following example shows how to change the first element of the numbers<\/code> list to 10:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nnumbers[0<\/span>] = 10<\/span>\n\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
[10<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The following shows how to multiply the second element by 10:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nnumbers[1<\/span>] = numbers[1<\/span>]*10<\/span>\n\nprint(numbers)\n<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
[1<\/span>, 30<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
And the following divides the third element by 2:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nnumbers[2<\/span>] \/= 2<\/span>\n\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
[1<\/span>, 3<\/span>, 1.0<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Adding elements to the list #<\/a><\/h3>\n\n\n\n
The append()<\/code> method appends an element to the end of a list. For example:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nnumbers.append(100<\/span>)\n\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
[1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>, 100<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The insert()<\/code> method adds a new element at any position in the list. <\/p>\n\n\n\n
For example, the following inserts the number 100 at index 2 of the numbers<\/code> list:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nnumbers.insert(2<\/span>, 100<\/span>)\n\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
[1<\/span>, 3<\/span>, 100<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Removing elements from a list #<\/a><\/h3>\n\n\n\n
The del<\/code> statement allows you to remove an element from a list by specifying the position of the element.<\/p>\n\n\n\n
The following example shows how to remove the first element from the list:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\ndel<\/span> numbers[0<\/span>]\n\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
[3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The pop()<\/code> method removes the last element from a list and returns that element:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\nlast = numbers.pop()\n\nprint(last)\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
4<\/span>\n[1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Typically, you use the pop()<\/code> method when you want to remove an element from a list and still want to access the value of that element.<\/p>\n\n\n\n
To pop an element by its position, you use the pop()<\/code> with the element’s index. For example:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]\n\nsecond = numbers.pop(1<\/span>)\n\nprint(second)\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
3<\/span>\n[1<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
To remove an element by value, you use the remove()<\/code> method. Note that the remove()<\/code> method removes only the first element it encounters in the list.<\/p>\n\n\n\n
For example, the following removes the element with value 9 from the numbers<\/code> list:<\/p>\n\n\n
numbers = [1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 9<\/span>, 4<\/span>, 9<\/span>]\n\nnumbers.remove(9<\/span>)\nprint(numbers)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
[1<\/span>, 3<\/span>, 2<\/span>, 7<\/span>, 4<\/span>, 9<\/span>]<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the remove()<\/code> method removes only the first number 9 but it doesn’t remove the second number 9 from the list.<\/p>\n\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
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