Sorted() function in Python
Python sorted() function returns a sorted list from the iterable object.
Sorted() sorts any sequence (list, tuple) and always returns a list with the elements in a sorted manner, without modifying the original sequence.
Syntax: sorted(iterable, key, reverse)
Parameters: sorted takes three parameters from which two are optional.
- Iterable : sequence (list, tuple, string) or collection (dictionary, set, frozenset) or any other iterator that needs to be sorted.
- Key(optional) : A function that would server as a key or a basis of sort comparison.
- Reverse(optional) : If set true, then the iterable would be sorted in reverse (descending) order, by default it is set as false.
Python sorted() function example
Example 1: Python sorted() list
Python3
x = [2, 8, 1, 4, 6, 3, 7]print("Sorted List returned :"),print(sorted(x))print("\nReverse sort :"),print(sorted(x, reverse=True))print("\nOriginal list not modified :"),print(x) |
Output:
Sorted List returned : [1, 2, 3, 4, 6, 7, 8] Reverse sort : [8, 7, 6, 4, 3, 2, 1] Original list not modified : [2, 8, 1, 4, 6, 3, 7]
Example 2: Sorting different data types
Python3
# Listx = ['q', 'w', 'r', 'e', 't', 'y']print(sorted(x))# Tuplex = ('q', 'w', 'e', 'r', 't', 'y')print(sorted(x))# String-sorted based on ASCII translationsx = "python"print(sorted(x))# Dictionaryx = {'q': 1, 'w': 2, 'e': 3, 'r': 4, 't': 5, 'y': 6}print(sorted(x))# Setx = {'q', 'w', 'e', 'r', 't', 'y'}print(sorted(x))# Frozen Setx = frozenset(('q', 'w', 'e', 'r', 't', 'y'))print(sorted(x)) |
Output:
['e', 'q', 'r', 't', 'w', 'y'] ['e', 'q', 'r', 't', 'w', 'y'] ['h', 'n', 'o', 'p', 't', 'y'] ['e', 'q', 'r', 't', 'w', 'y'] ['e', 'q', 'r', 't', 'w', 'y'] ['e', 'q', 'r', 't', 'w', 'y']
Example 3: Python sorted reverse
Python3
# Python3 code to demonstrate# Reverse Sort a String# using join() + sorted() + reverse # initializing stringtest_string = "geekforgeeks" # printing original stringprint("The original string : " + str(test_string)) # using join() + sorted() + reverse# Sorting a stringres = ''.join(sorted(test_string, reverse = True)) # print resultprint("String after reverse sorting : " + str(res)) |
Output:
The original string : geekforgeeks String after reverse sorting : srokkggfeeee
Example 4: Python sorted() lambda
Python3
# Python code to demonstrate# Reverse Sort a String# using sorted() + reduce() + lambda# import the moduleimport functools# initializing stringtest_string = "geekforgeeks"# printing original stringprint("The original string : " + str(test_string))# using sorted() + reduce() + lambda# Reverse Sort a Stringres = functools.reduce(lambda x, y: x + y, sorted(test_string, reverse=True))# print resultprint("String after reverse sorting : " + str(res)) |
Output:
The original string : geekforgeeks String after reverse sorting : srokkggfeeee
Python sorted() key
sorted() function has an optional parameter called ‘key’ which takes a function as its value. This key function transforms each element before sorting, it takes the value and returns 1 value which is then used within sort instead of the original value. For example, if we pass a list of strings in sorted(), it gets sorted alphabetically. But if we specify key = len, i.e. give len function as key, then the strings would be passed to len, and the value it returns, i.e. the length of strings will be sorted. This means that the strings would be sorted based on their lengths instead
Python3
L = ["cccc", "b", "dd", "aaa"]print("Normal sort :", sorted(L))print("Sort with len :", sorted(L, key=len)) |
Output:
Normal sort : ['aaa', 'b', 'cccc', 'dd'] Sort with len : ['b', 'dd', 'aaa', 'cccc']
Key can also take user-defined functions as its value for the basis of sorting.
Python3
# Sort a list of integers based on# their remainder on dividing from 7def func(x): return x % 7L = [15, 3, 11, 7]print("Normal sort :", sorted(L))print("Sorted with key:", sorted(L, key=func)) |
Output:
Normal sort : [3, 7, 11, 15] Sorted with key: [7, 15, 3, 11]
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