Here we created a list containing floating point numbers, then used the sort method without passing any additional parameter, and printed the list.<\/p>\n\n\n
\ninput = [1.2, 221, 0.025, 0.124, 1.2]\n\nprint(f'Before: {input}')\n\ninput.sort()\n\nprint(f'After: {input}')\n\n<\/pre><\/div>\n\n\nOutput:<\/strong><\/p>\n\n\n\nBefore : [1.2, 221, 0.025, 0.124, 1.2]\nAfter : [0.025, 0.124, 1.2, 1.2, 221]<\/code><\/pre>\n\n\n\nIn the above output, you can see that the list values are sorted in ascending order.<\/p>\n\n\n\n
2. Sort the List Elements in Descending Order<\/h3>\n\n\n\n
Descending refers to arranging the highest value on the left side and decreasing toward the lowest value on the right side.<\/p>\n\n\n\n
To sort a list in descending order, the value passed to the reverse parameter should be True.<\/p>\n\n\n\n
Syntax: <\/strong> <\/p>\n\n\n\nlist_name.sort(reverse=True)\n<\/pre><\/div>\n\n\nExample:<\/strong><\/p>\n\n\n\nHere we created a list containing numbers, then used the sort method, passed an additional parameter \u201creverse=True\u201d to sort the list in descending order, and printed the list.<\/p>\n\n\n
\ninput = [8, 1, 12, 0]\n\ninput.sort(reverse = True)\n\nprint(input)\n<\/pre><\/div>\n\n\nOutput:<\/strong><\/p>\n\n\n\n[12, 8, 1, 0]<\/code><\/pre>\n\n\n\nIn the above output, you can see that the list values are sorted in descending order.<\/p>\n\n\n\n
3. Sort the List using a Key Function<\/h3>\n\n\n\n
A list can sort on the bases of some predefined order. It is required to create a function that defines the criteria, and then pass the name of that function to the key parameter inside the sort() method. <\/p>\n\n\n\n
Let\u2019s see an example for more clearance.<\/p>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\nHere we have defined a function that returns the third element of the values of the list, this function has then passed as a key to the sort() method to sort based on the third element of the values.<\/p>\n\n\n
\n# takes third element for sort\ndef third_element(x):\n return x[2]\n\n\ninput = [(2, 2, 1), (3, 4, 9), (4, 1, 0), (1, 3, 7)]\n\n# sort list with key\ninput.sort(key=third_element)\n\n# prints sorted list\nprint('Sorted list:', input)\n<\/pre><\/div>\n\n\nOutput:<\/strong><\/p>\n\n\n\nSorted list: [(4, 1, 0), (2, 2, 1), (1, 3, 7), (3, 4, 9)]<\/code><\/pre>\n\n\n\nThe above output shows that the list values are sorted in ascending order of their third element.<\/p>\n\n\n\n
4. Sort the List using User-defined Order<\/h3>\n\n\n\n
Again, we can use the key parameter to pass a function to define our own sort order.<\/p>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\n# takes third element for sort\ndef third_element(x):\n return x[2]\n\n\ninput = [(2, 2, 1), (3, 4, 9), (4, 1, 0), (1, 3, 7)]\n\n# sorts list with key in ascending order\ninput.sort(key=third_element)\n\n# prints sorted list\nprint('Sorted list in ascending order:', input)\n\n# sorts list with key in descending order\ninput.sort(key=third_element, reverse=True)\n\nprint('Sorted list in descending order:', input)\n<\/pre><\/div>\n\n\nOutput:<\/strong><\/p>\n\n\n\nSorted list in ascending order: [(4, 1, 0), (2, 2, 1), (1, 3, 7), (3, 4, 9)]\nSorted list in descending order: [(3, 4, 9), (1, 3, 7), (2, 2, 1), (4, 1, 0)]<\/code><\/pre>\n\n\n\nThe above output shows that the list values are sorted in ascending and descending order of their third element.<\/p>\n\n\n\n
5. Sort the List of Class Objects<\/h3>\n\n\n\n
In order to sort the list of custom objects using the sort() function, you need to define the key function specifying the object\u2019s field, based on which you want to sort the list elements.<\/p>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\nclass Details:\n\n def __init__(self, name, num):\n self.name = name\n self.num = num\n\n\n def __str__(self):\n return f'Details[{self.name}:{self.num}]'\n\n\n __repr__ = __str__\n\n\nD1 = Details('Safa', 12)\nD2 = Details('Aman', 1)\nD3 = Details('Shalini', 45)\nD4 = Details('Ruh', 30)\n\ninput_list = [D1, D2, D3, D4]\n\nprint(f'Before Sorting: {input_list}')\n\n\n\ndef sort_by_num(details):\n return details.num\n\n\ninput_list.sort(key=sort_by_num)\nprint(f'After Sorting By Number: {input_list}')\n<\/pre><\/div>\n\n\nIn the above code example, we have created a class, and from that class, we have created multiple objects and passed them inside a list, and printed that list, you can see that the list printed has all the objects.<\/p>\n\n\n\n
In order to sort its object we then defined a function, notice how we defined the return value to be a specific object\u2019s field(num), which will be the criteria for sort. After passing the function to the sort method, we again printed the list. <\/p>\n\n\n\n
Output:<\/strong><\/p>\n\n\n\nBefore Sorting: [Details[Safa:12], Details[Aman:1], Details[Shalini:45], Details[Ruh:30]]\nAfter Sorting By Number: [Details[Aman:1], Details[Safa:12], Details[Ruh:30], Details[Shalini:45]]<\/code><\/pre>\n\n\n\nYou can see that the list object is sorted in ascending order to their num field. Hence the output is justified.<\/p>\n\n\n\n
Conclusion<\/h2>\n\n\n\n
In this tutorial, we have explained the sort() method which is used to sort a list in python. This method takes two arguments, the first one is “reverse” <\/strong>which contains a boolean value that defines the sort order, where False represents ascending order and True represents descending order. The second argument is a “key”<\/strong> which contains a function that defines the criteria to sort, such as based on some field, length, etc. <\/p>\n\n\n\nWe have also covered the different approaches to this method to sort, such as in ascending order, descending order, on the basis of custom or user-defined criteria, etc. We also discussed the process to sort a list of class objects. Hope this tutorial helps you to sort the list in python.<\/p>\n\n\n\n
References<\/h2>\n\n\n\n
Sorting documentation<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"Python\u2019s list sort() method is used to sort a list in either ascending or descending order, additionally, you can also define the criteria to sort.\u00a0 This tutorial will provide a complete guide to all types of list sorting in Python using the sort() method. Overview of List Sorting Sorting is a technique to rearrange items. […]<\/p>\n","protected":false},"author":3,"featured_media":39722,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[480],"class_list":["post-2393","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-list","tag-python-sort-list"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts\/2393","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/comments?post=2393"}],"version-history":[{"count":0,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts\/2393\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/media\/39722"}],"wp:attachment":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/media?parent=2393"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/categories?post=2393"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/tags?post=2393"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}