Python List Sort by a key |Python examples for beginners to Advance |My programming school


Python List Sort Flowchart

From this tutorial, you’ll be studying about Python checklist Sort by a key technique. You will see how to use it with lists with the assistance of examples.

Note: The syntax used in the beneath part is for Python 3. You can change it to another variations of Python.

Python List Sort

To Learn about Lists – Read Python List

List Sort Method

The sort technique performs the sorting of checklist components in both ascending or descending route. Its syntax is as follows:

List_name.sort(key = …, reverse = ...)

When the sort() will get known as with out arguments, it kinds in the ascending order by default. It doesn’t have a return worth.

It merely returns to the subsequent line with out returning any output.

Please be aware that it is not associated to the built-in sorted() operate. The sort technique mutates or modifies an previous checklist whereas sorted() creates a new sorted sequence.

How does the Sort technique work?

When we name this technique, it traverses the checklist components in a loop and rearranges them in ascending order when there aren’t any arguments.

If we specify “reverse = true” as an argument, then the checklist will get sorted in the descending order.

The main parameter is the steps that the tactic should undergo when sorting by way of a checklist of components. The worth given to the key will be a operate or a easy calculation and so on.

The flowchart for the mechanism is as follows:

Python List Sort Flowchart
Python checklist sort by

Sort Method Examples

Sort a checklist of numbers:

a. Sorting a checklist of numbers in ascending order

Natural_numbers = [1,4,23,3,2,1,0,9,7]

Natural_numbers.sort()

print (Natural_numbers)

Output:

[0, 1, 1, 2, 3, 4, 7, 9, 23]

b. Sorting a checklist of numbers in descending order

Natural_numbers = [1,23,4,25,22,3,4,5,9,7,5]

Natural_numbers.sort(reverse = True)

print (Natural_numbers)

Output:

[25, 23, 22, 9, 7, 5, 5, 4, 4, 3, 1]

Sort a checklist of letters:

a. Sorting a checklist of letters in ascending order

Vowels = ["a", "u", "i", "o", "e"]

Vowels.sort()

print (Vowels)

Output:

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

b. Sorting a checklist of letters in descending order

Vowels = ["a", "u", "i", "o", "e"]

Vowels.sort(reverse = True)

print (Vowels)

Output:

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

Sort a checklist of strings:

a. Sorting a checklist of strings in ascending order

Fruits = ["Apple", "Banana", "Tomato", "Grapes"]

Fruits.sort()

print (Fruits)

Output:

['Apple', 'Banana', 'Grapes', 'Tomato']

b. Sorting a checklist of strings in descending order

Fruits = ["Apple", "Banana", "Tomato", "Grapes"]

Fruits.sort(reverse = True)

print (Fruits)

Output:

['Tomato', 'Grapes', 'Banana', 'Apple']

Python List Sort by a key operate:

a. Sorting a checklist by a key operate (ascending)

# Let's sort on the idea of 2nd factor
def keyFunc(merchandise):
    return merchandise[1]

# Unordered checklist
unordered = [('b', 'b'), ('c', 'd'), ('d', 'a'), ('a', 'c')]

# Order checklist utilizing key
unordered.sort(key=keyFunc)

# Output the sorted checklist
print('Ordered checklist:', unordered)

Output:

Ordered checklist: [('d', 'a'), ('b', 'b'), ('a', 'c'), ('c', 'd')]

b. Sorting a checklist utilizing a key operate (descending)

# Let's sort on the idea of 2nd factor
def keyFunc(merchandise):
    return merchandise[1]

# Unordered checklist
unordered = [('b', 'b'), ('c', 'd'), ('d', 'a'), ('a', 'c')]

# Order checklist utilizing key in the reverse route
unordered.sort(key=keyFunc, reverse = True)

# Output the sorted checklist
print('Ordered checklist:', unordered)

Output:

Ordered checklist: [('c', 'd'), ('a', 'c'), ('b', 'b'), ('d', 'a')]

Python List Sort by a key |Python examples for beginners to Advance |My programming school
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