{"id":2548,"date":"2020-08-06T02:05:44","date_gmt":"2020-08-06T02:05:44","guid":{"rendered":"https:\/\/www.afternerd.com\/blog\/?p=2548"},"modified":"2020-08-06T02:05:45","modified_gmt":"2020-08-06T02:05:45","slug":"sort-vs-sorted","status":"publish","type":"post","link":"https:\/\/www.afternerd.com\/blog\/sort-vs-sorted\/","title":{"rendered":"Python: Sort vs Sorted"},"content":{"rendered":"\n

In Python, you can use sort<\/strong> or sorted<\/strong> to sort a list.<\/p>\n\n\n\n

But what is the difference between the two? This is what I will discuss in this article.<\/p>\n\n\n\n

First: Sorting a Python List using Sort<\/h2>\n\n\n\n

sort()<\/span> is a method<\/a> on the list object.<\/p>\n\n\n\n

Say, you have an arbitrary list L<\/span> and you want to sort it. Here is what you can do.<\/p>\n\n\n\n

>>> L = [5, 3, 7]\n>>> L.sort()\n>>> L\n[3, 5, 7]<\/code><\/pre>\n\n\n\n
There is one thing that I want to notice: L was sorted in-place. This means that no new<\/em> lists were created.<\/p>\n\n\n\n
You can double check that using the id<\/span> built-in function.<\/p>\n\n\n\n
>>> L = [5, 3, 7]\n>>> id(L)\n4477543040\n>>> L.sort()\n>>> L\n[3, 5, 7]\n>>> id(L)\n4477543040<\/code><\/pre>\n\n\n\n
Having the same id means that the location of the object is the same before and after sorting, which confirms that sorting happened in-place.<\/p>\n\n\n\n
Now let’s talk about sorted().<\/p>\n\n\n\n
Second: Sorting a Python List using Sorted<\/h2>\n\n\n\n
Unlike sort, sorted is not a method.<\/p>\n\n\n\n
sorted()<\/strong> is a built-in function like print()<\/strong> or id()<\/strong>.<\/p>\n\n\n\n
Let’s try to use sorted to sort the same list from above.<\/p>\n\n\n\n
>>> L = [5, 3, 7]\n>>> sorted(L)\n[3, 5, 7]\n>>> L\n[5, 3, 7]<\/code><\/pre>\n\n\n\n
It doesn’t seem to work, does it? It looks like L<\/strong> hasn’t changed. Why is that?<\/p>\n\n\n\n
Unlike sort, sorted creates a new list object<\/em> and sorts the elements of the original list L<\/strong> in this new object without modifying the original list.<\/p>\n\n\n\n
This is an essential difference between sort and sorted.<\/p>\n\n\n\n
You can easily confirm that by inspecting the ids.<\/p>\n\n\n\n
>>> L = [5, 3, 7]\n>>> id(L)\n4477542848\n>>> id(sorted(L))\n4477542976<\/code><\/pre>\n\n\n\n
So with that in mind, the correct way to use sorted is as follows:<\/p>\n\n\n\n
>>> L = [5, 3, 7]\n>>> Q = sorted(L)\n>>> Q\n[3, 5, 7]<\/code><\/pre>\n\n\n\n
So essentially, if you want to sort the elements of a list in place, use the sort<\/strong> method. But if you want to sort the items of a list in a new list object without modifying the original list, use the sorted<\/strong> built-in function.<\/p>\n\n\n\n
What sorting algorithm is used for sort and sorted?<\/h2>\n\n\n\n
Both sort<\/strong> and sorted<\/strong> use the\u00a0Timsort<\/a>\u00a0sorting algorithm which is a hybrid sorting algorithm between merge sort<\/a> and insertion sort<\/a>.<\/p>\n\n\n\n
If you want to know more about Timsort and its superior performance, then I highly recommend reading this<\/a>.<\/p>\n\n\n\n
Advanced Questions<\/h2>\n\n\n\n