Python – Sort by Maximum digit in Element

When it is required to sort by maximum digit in element, a method is defined that uses str() and max() method to determine the result. This technique converts each number to a string, finds its largest digit, and uses that digit as the sorting key.

Syntax

def max_digits(element):
    return max(str(element))

list.sort(key=max_digits)

Example

Here's how to sort a list of numbers by their maximum digit ?

def max_digits(element):
    return max(str(element))

my_list = [224, 192, 145, 18, 3721]

print("The list is :")
print(my_list)

my_list.sort(key=max_digits)

print("The result is :")
print(my_list)

The list is :
[224, 192, 145, 18, 3721]
The result is :
[224, 145, 3721, 18, 192]

How It Works

The sorting works by comparing the maximum digits:

• 224 ? max digit is '4'
• 192 ? max digit is '9'
• 145 ? max digit is '5'
• 18 ? max digit is '8'
• 3721 ? max digit is '7'

Sorted order by max digit: '4' < '5' < '7' < '8' < '9'

Using Lambda Function

You can achieve the same result with a lambda function ?

numbers = [567, 834, 921, 456, 123]

print("Original list:", numbers)

sorted_list = sorted(numbers, key=lambda x: max(str(x)))

print("Sorted by max digit:", sorted_list)

Original list: [567, 834, 921, 456, 123]
Sorted by max digit: [123, 456, 567, 834, 921]

Conclusion

Use max(str(element)) as a sorting key to order numbers by their largest digit. The str() function converts numbers to strings, allowing max() to find the highest character value.