The sort function can be used to sort the list in both ascending and descending order. It can be used to sort lists of integers, floating point numbers, strings, and others in Python. Its time complexity is O(NlogN).
Python sort() Syntax
The syntax of the sort() function in Python is as follows.
Syntax: list_name.sort(key=…, reverse=…)
Parameters:
By default, Python sort() doesn’t require any extra parameters and sorts the list in ascending order. However, it has two optional parameters:
- key: function that serves as a key for the sort comparison
- reverse: If true, the list is sorted in descending order.
Return value: The sort() does not return anything but alters the original list according to the passed parameter.
Sort() in Python Examples
A basic example of Python sort() method.
Python3
unsorted_list = [2,4,5,32,6,255,5,42]unsorted_list.sort()print("Now it is sorted:", unsorted_list) |
Now it is sorted: [2, 4, 5, 5, 6, 32, 42, 255]
In Python, sort() is a built-in method used to sort elements in a list in ascending order. It modifies the original list in place, meaning it reorders the elements directly within the list without creating a new list. The sort() method does not return any value; it simply sorts the list and updates it.
- Sorting List in Ascending Order
- Sorting List in Descending Order
- Sort with custom function using key
- Difference between sorted() and sort() function in Python
Sorting List in Ascending Order
By default, the sort() in Python sorts a list in ascending order if we do not provide it with any parameters.
Python3
# List of Integersnumbers = [1, 3, 4, 2]# Sorting list of Integersnumbers.sort()print(numbers)# List of Floating point numbersdecimalnumber = [2.01, 2.00, 3.67, 3.28, 1.68]# Sorting list of Floating point numbersdecimalnumber.sort()print(decimalnumber)# List of stringswords = ["Geeks", "For", "Geeks"]# Sorting list of stringswords.sort()print(words) |
[1, 2, 3, 4] [1.68, 2.0, 2.01, 3.28, 3.67] ['For', 'Geeks', 'Geeks']
Sorting List in Descending Order
To sort a list in descending order, set the reverse parameter to True of the sort() function in Python.
Python3
# List of Integersnumbers = [1, 3, 4, 2]# Sorting list of Integersnumbers.sort(reverse=True)print(numbers)# List of Floating point numbersdecimalnumber = [2.01, 2.00, 3.67, 3.28, 1.68]# Sorting list of Floating point numbersdecimalnumber.sort(reverse=True)print(decimalnumber)# List of stringswords = ["Geeks", "For", "Geeks"]# Sorting list of stringswords.sort(reverse=True)print(words) |
[4, 3, 2, 1] [3.67, 3.28, 2.01, 2.0, 1.68] ['Geeks', 'Geeks', 'For']
Sort with Custom Function using Key
To sort the list according to the user’s choice, pass a function to the key parameter of the Python sort() function.
Python3
def sortSecond(val): return val[1]# list1 to demonstrate the use of sorting# using second keylist1 = [(1,2),(3,3),(1,1)]# sorts the array in ascending according to# second elementlist1.sort(key=sortSecond)print(list1)# sorts the array in descending according to# second elementlist1.sort(key=sortSecond,reverse=True)print(list1) |
[(1, 1), (1, 2), (3, 3)] [(3, 3), (1, 2), (1, 1)]
Difference between sorted() and sort() function in Python
Let us see the difference between the sorted() and sort() function in Python:
|
Python sorted() |
Python sort() |
|---|---|
| The sorted() function returns a sorted list of the specific iterable object. | The sort() method sorts the list. |
| We can specify ascending or descending order while using the sorted() function | It sorts the list in ascending order by default. |
| Syntax: sorted(iterable, key=key, reverse=reverse) | Syntax: list.sort(reverse=True|False, key=myFunc) |
| Its return type is a sorted list. | We can also use it for sorting a list in descending order. |
| It can only sort a list that contains only one type of value. | It sorts the list in place. |
To know more please refer Python difference between the sorted() and sort() function.
