[Python] Manipulating elements in a list (array) [Sort]

Introduction

We have summarized the ** sorting ** methods that are important for working with lists. Basically, write the code and output result with the following code.

ex.py

code = 'code'
print(code)
# code(Output result)

Sort the list in ascending or descending order sort (), sorted ()

There are two ways to sort a list in ascending or descending order in Python: sort () and sorted (). Use sorted () if you want to sort strings and tuples.

· Sort (): sort the original list

** * Destructive processing that rewrites the original list itself. ** **

sort().py

org_list = [3, 1, 4, 5, 2]

org_list.sort()
print(org_list)
# [1, 2, 3, 4, 5]

#sort()Note that returns None.
print(org_list.sort())
# None

#The default is ascending order. If you want to sort in descending order, set the argument reverse to True.
org_list.sort(reverse=True)
print(org_list)
# [5, 4, 3, 2, 1]

sorted (): Generate a new sorted list

** * If you specify the list you want to sort in the argument, the sorted list is returned. Non-destructive processing that does not change the original list. ** **

sorted().py

org_list = [3, 1, 4, 5, 2]

new_list = sorted(org_list)
print(org_list)
# [3, 1, 4, 5, 2]
print(new_list)
# [1, 2, 3, 4, 5]

#The default is ascending order. If you want to sort in descending order, set the argument reverse to True.
new_list_reverse = sorted(org_list, reverse=True)
print(org_list)
# [3, 1, 4, 5, 2]
print(new_list_reverse)
# [5, 4, 3, 2, 1]

Sorting strings using sorted ()

If a character string is specified as an argument of the sorted () function, a ** list ** in which each character of the sorted character string is stored as an element is returned.

sorted()_.py

org_str = 'cebad'
print(org_str)
# cebad

new_str_list = sorted(org_str)
print(new_str_list)
# ['a', 'b', 'c', 'd', 'e']

#Join to concatenate a list of strings into a single string()Use the method.
new_str = ''.join(new_str_list)
print(new_str)
# abcde

#You can write them all together. If you want to sort in descending order, set the argument reverse to True.
new_str_reverse = ''.join(sorted(org_str, reverse=True))
print(new_str_reverse)
# edcba

Reverse (), reversed () to sort lists and strings in reverse order

There are ways to sort the elements of a list in reverse order in Python using reverse (), reversed () and slices. Use reversed () or slices if you want to sort strings or tuples in reverse order.

· Reverse (): Sort the original list in reverse order

** * Destructive processing that rewrites the original list itself. ** **

sort().py

org_list = [1, 2, 3, 4, 5]

org_list.reverse()
print(org_list)
# [5, 4, 3, 2, 1]

#reverse()Note that returns None.
print(org_list.reverse())
# None

-Reversed (): Generates an iterator to retrieve in reverse order

** * reversed () returns an iterator that retrieves the elements in reverse order. Non-destructive processing that does not change the original list. ** **

sort().py

org_list = [1, 2, 3, 4, 5]

reverse_iterator = reversed(org_list)
print(org_list)
# [1, 2, 3, 4, 5]

#reversed()Note that returns an iterator instead of a list. list()Convert the iterator to a list with.
new_list = list(reversed(org_list))
print(new_list)
# [5, 4, 3, 2, 1]

・ Sort in reverse order by slice

ex.py

org_list = [1, 2, 3, 4, 5]
new_list = org_list[::-1]
print(new_list)
# [5, 4, 3, 2, 1]

org_str = 'abcde'
new_str = org_str[::-1]
print(new_str)
# edcba

Finally

I would be grateful if you could tell me if there is any other solution.