{"id":68,"date":"2024-01-25T09:33:04","date_gmt":"2024-01-25T09:33:04","guid":{"rendered":"https:\/\/learnpython.elegantwallp.com\/?p=68"},"modified":"2024-01-25T09:33:05","modified_gmt":"2024-01-25T09:33:05","slug":"python-sort-list","status":"publish","type":"post","link":"https:\/\/learnpython.elegantwallp.com\/2024\/01\/25\/python-sort-list\/","title":{"rendered":"Python Sort List"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you\u2019ll learn how to use the Python List sort()<\/code> method to sort a list.<\/p>\n\n\n\n

Introduction to the Python List sort()<\/code> method<\/h2>\n\n\n\n

To sort a\u00a0list, you use the\u00a0sort()<\/code>\u00a0method:<\/p>\n\n\n\n

list.sort()<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
The sort()<\/code> method sorts the original list in place. It means that the sort()<\/code> method modifies the order of elements in the list.<\/p>\n\n\n\n
By default, the sort()<\/code> method sorts the elements of a list using the less-than operator (<<\/code>). In other words, it places the lower elements before the higher ones.<\/p>\n\n\n\n
To sort elements from higher to lower, you pass the\u00a0reverse=True<\/code>\u00a0argument to the\u00a0sort()<\/code>\u00a0method like this:<\/p>\n\n\n\n
list.sort(reverse=True)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Python List sort() method examples<\/h2>\n\n\n\n
Let\u2019s take some examples of using the sort()<\/code> method.<\/p>\n\n\n\n
1) Using the Python List sort() method to sort a list of strings<\/h3>\n\n\n\n
If a list contains strings, the sort()<\/code> method sorts the string elements alphabetically.<\/p>\n\n\n\n
The following example uses the\u00a0sort()<\/code>\u00a0method to sort the elements in the\u00a0guests<\/code>\u00a0list alphabetically:<\/p>\n\n\n\n
guests = ['James', 'Mary', 'John', 'Patricia', 'Robert', 'Jennifer'] guests.sort() print(guests)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
['James', 'Jennifer', 'John', 'Mary', 'Patricia', 'Robert']<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
And the following example uses the\u00a0sort()<\/code>\u00a0method with the\u00a0reverse=True<\/code>\u00a0argument to sort the elements in the\u00a0guests<\/code>\u00a0list in the reverse alphabetical order:<\/p>\n\n\n\n
guests = ['James', 'Mary', 'John', 'Patricia', 'Robert', 'Jennifer'] guests.sort(reverse=True) print(guests)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
['Robert', 'Patricia', 'Mary', 'John', 'Jennifer', 'James']<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
2) Using the Python List sort() method to sort a list of numbers<\/h3>\n\n\n\n
If a list contains numbers, the sort()<\/code> method sorts the numbers from smallest to largest.<\/p>\n\n\n\n
The following example uses the\u00a0sort()<\/code>\u00a0method to sort numbers in the\u00a0scores<\/code>\u00a0list from smallest to largest:<\/p>\n\n\n\n
scores = [5, 7, 4, 6, 9, 8] scores.sort() print(scores)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
[4, 5, 6, 7, 8, 9]<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
To sort numbers from the largest to smallest, you use the\u00a0sort(reverse=True)<\/code>\u00a0like this:<\/p>\n\n\n\n
scores = [5, 7, 4, 6, 9, 8] scores.sort(reverse=True) print(scores)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
[9, 8, 7, 6, 5, 4]<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
3) Using the Python List sort() method to sort a list of tuples<\/h3>\n\n\n\n
Suppose that you have a list of tuples like this:<\/p>\n\n\n\n
companies = [('Google', 2019, 134.81), ('Apple', 2019, 260.2), ('Facebook', 2019, 70.7)]<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
And you want to sort the companies list by revenue from highest to lowest. To do it:<\/p>\n\n\n\n
First, specify a sort key and pass it to the\u00a0sort()<\/code>\u00a0method. To define a sort key, you create a function that accepts a tuple and returns the element that you want to sort by:<\/p>\n\n\n\n
def sort_key(company): return company[2]<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
This sort_key()<\/code> function accepts a tuple called company<\/code> and returns the third element.<\/p>\n\n\n\n
Note that the company is a tuple e.g., ('Google', 2019, 134.81)<\/code>. And the company[2]<\/code> references the revenue like 134.81<\/code> in this case.<\/p>\n\n\n\n
Second, pass the sort_key function to the\u00a0sort()<\/code>\u00a0method:<\/p>\n\n\n\n
companies.sort(key=sort_key, reverse=True)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
The sort()<\/code> method will use the value returned by the sort_key()<\/code> function for the comparisons.<\/p>\n\n\n\n
Note that you just pass the function name without the parentheses to the\u00a0sort()<\/code>\u00a0method:<\/p>\n\n\n\n
companies = [('Google', 2019, 134.81), ('Apple', 2019, 260.2), ('Facebook', 2019, 70.7)] # define a sort key<\/em> def sort_key(company): return company[2] # sort the companies by revenue<\/em> companies.sort(key=sort_key, reverse=True) # show the sorted companies<\/em> print(companies) <\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
[('Apple', 2019, 260.2), ('Google', 2019, 134.81), ('Facebook', 2019, 70.7)]<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Using lambda expression<\/h4>\n\n\n\n
To make it more concise, Python allows you to define a function without a name with the following syntax:<\/p>\n\n\n\n
lambda arguments: expression<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
A function without a name is called an\u00a0anonymous function<\/strong>. And this syntax is called a\u00a0lambda expression.<\/p>\n\n\n\n
Technically, it\u2019s equivalent to the following function:def name(arguments): return expression<\/code>Code language: Python (python)<\/small><\/p>\n\n\n\n
The following example uses the lambda expression to sort the companies by revenue from low to high:<\/p>\n\n\n\n
companies = [('Google', 2019, 134.81), ('Apple', 2019, 260.2), ('Facebook', 2019, 70.7)] # sort the companies by revenue<\/em> companies.sort(key=lambda company: company[2]) # show the sorted companies<\/em> print(companies)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
[('Apple', 2019, 260.2), ('Google', 2019, 134.81), ('Facebook', 2019, 70.7)]<\/code><\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
Summary: in this tutorial, you\u2019ll learn how to use the Python List sort() method to sort a list. Introduction to the Python List sort() method To sort a\u00a0list, you use the\u00a0sort()\u00a0method: The sort() method sorts the original list in place. It means that the sort() method modifies the order of elements in the list. By default, the sort() method sorts the elements of a list […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[19],"tags":[],"class_list":["post-68","post","type-post","status-publish","format-standard","hentry","category-5-lists"],"_links":{"self":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/68","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/comments?post=68"}],"version-history":[{"count":1,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/68\/revisions"}],"predecessor-version":[{"id":69,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/68\/revisions\/69"}],"wp:attachment":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/media?parent=68"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/categories?post=68"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/tags?post=68"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}