Python sort list (Array) | sorted function – Strings (alphabetically), Number, list

The python sort() function is used to sorts the elements of a given list. It sorts the list ascending, descending, or user-defined order where ascending order is by default.

Note:

  1. Ascending order is by default in sort() method.
  2. It changes the original list and doesn’t return any value.

Syntax

list.sort(reverse=True|False, key=myFunc)

Parameter Values

Both parameters are Optional.

  • reverse:- if reverse = True will sort the list descending else as Default is (reverse=False)
  • key:- A function to specify the sorting criteria(s)

Python sort list using sort function example

1. Sort the list “Ascending” order:

Numbers

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

# Sorting list of Integers in ascending 
numbers.sort()

print(numbers)

Output:

Python sort list Array

Strings

Example of how to python sort a list of strings.

# vowels list
vowels = ['e', 'a', 'u', 'o', 'i']

# sort the vowels
vowels.sort()

# print vowels
print('Sorted list:', vowels)

Output:

Sorted list: ['a', 'e', 'i', 'o', 'u']

2. Sort the list “descending” order

Use and Set the parameter reverse=True sorts the list in descending order.

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

# Sorting list descending
numbers.sort(reverse=True)

print(numbers)

Output: [5, 4, 3, 2, 1]

Q: How to sort the list of lists in python?

Answer: If you want to sort on more entries, just make the key function return a tuple containing the values you wish to sort on in order of importance. For example:

c2.sort(key = lambda row: (row[2],row[1],row[0]))

Complete example

c2 = []
row1 = [1, 22, 53]
row2 = [14, 25, 46]
row3 = [7, 8, 9]

c2.append(row2)
c2.append(row1)
c2.append(row3)

# OR direct can use
# c2 = [[14, 25, 46], [1, 22, 53], [7, 8, 9]]

c2.sort(key=lambda row: (row[2], row[1], row[0]))
print(c2)

Output: [[7, 8, 9], [14, 25, 46], [1, 22, 53]]

Q: How to sort the list alphabetically in Python?

Answer: Use The sorted() function returns a sorted  list where Strings are sorted alphabetically.

a = ("b", "g", "a", "d", "f", "c", "h", "e")

print(sorted(a))

Output: [‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’, ‘g’, ‘h’]

Do comment if you have any doubts, something missing (you think must cover here), and suggestions on this tutorial.

Note:
IDE: PyCharm 2020.1.1 (Community Edition)
macOS 10.15.4
Python 3.7
All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.


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