Python sorted() usage and examples

Python built-in functions

sorted() function returns a sorted list in an iterative manner.

sorted() function returns a sorted list in a specific order (AscendingorDescending) to sort the given iterable elements.

The syntax of sorted() is:

sorted(iterable, key=None, reverse=False)

sorted() parameters

sorted() can use up to three parameters:

• iterable-Sequence(String,Tuple,List) or set(Set,Dictionary,Frozen set) or any other iterator.

• reverse (optional) -If set to True, the sorted list will be reversed (or sorted in descending order). If not provided, the default is False.

• key (optional) -Used as a function for sorting comparison key. The default is None.

Example1: Sorting strings, lists, and tuples

# Vowel list
py_list = ['e', 'a', 'u', 'o', 'i']
print(sorted(py_list))
# string　
py_string = 'Python'
print(sorted(py_string))
# Vowel tuple
py_tuple = ('e', 'a', 'u', 'o', 'i')
print(sorted(py_tuple))

Output result

['a', 'e', 'i', 'o', 'u']
['P', 'h', 'n', 'o', 't', 'y']
['a', 'e', 'i', 'o', 'u']

Note:The list also hassort()Method, which operates in the same way as sort(). The only difference is that the sort() method does not return any value and changes the original list.

Example2: Descending order: set, dictionary, and frozen set

The sorted() function accepts a reverse parameter as an optional argument.

Set reverse = True to sort the iterable in reverse order.

#　set
py_set　=　{'e',　'a',　'u',　'o',　'i'}
print(sorted(py_set,　reverse　=　True))
#　dictionary
py_dict　=　{'e':　1,　'a':　2,　'u':　3,　'o':　4,　'i':　5}
print(sorted(py_dict,　reverse　=　True))
#　frozen set
frozen_set　=　frozenset(('e',　'a',　'u',　'o',　'i'))
print(sorted(frozen_set,　reverse　=　True))

Output result

['u',　'o',　'i',　'e',　'a']
['u',　'o',　'i',　'e',　'a']
['u',　'o',　'i',　'e',　'a']

Key parameters of Python's sorted()

If you want to sort using your own implementation, then sort() also accepts a key function as an optional parameter.

You can sort the given iterable according to the result of the key function.

sorted(iterable,　key=len)

len()　is a built-in function in Python, used to calculate the length of an object.

The list is sorted according to the length of the elements (from the lowest to the highest count).

Example3：Use sorted() with a key function to sort the list

#　Sort by the second element
def　take_second(elem):
　　　　return　elem[1]
#　Random list
random　=　[(2,　2),　(3,　4),　(4,　1),　(1,　3)]
#　Key sorted list
sorted_list　=　sorted(random,　key　=　take_second)
#　Print list
print('Sorted list:',　sorted_list)

Output result

Sorted list:　[(4,　1),　(2,　2),　(1,　3),　(3,　4)]

Python built-in functions