How to Sort a List by Existing Properties in Python

What is the best way to sort a list by existing properties in Python?

my_list = [{'name': 'Alice', 'age': 30}, {'name': 'Bob', 'age': 25}, {'name': 'Charlie', 'age': 35}]

sorted_list = sorted(my_list, key=lambda x: x['age'])
print(sorted_list)  # Output: [{'name': 'Bob', 'age': 25}, {'name': 'Alice', 'age': 30}, {'name': 'Charlie', 'age': 35}]

In Python, sorting a list of dictionaries by a specific property is straightforward using the built-in `sorted()` function along with a custom key function. This allows you to specify which property of the dictionaries to sort by, making it flexible and easy to implement.

my_list = [{'name': 'Alice', 'age': 30}, {'name': 'Bob', 'age': 25}, {'name': 'Charlie', 'age': 35}]

# Sort by age
sorted_list = sorted(my_list, key=lambda x: x['age'])
print(sorted_list)  # Output: [{'name': 'Bob', 'age': 25}, {'name': 'Alice', 'age': 30}, {'name': 'Charlie', 'age': 35}]

Causes

• Misunderstanding the use of the key parameter in sorting functions.
• Improper data structure where properties are not accessible as expected.
• Confusion between sorting in ascending and descending order.

Solutions

• Use the `sorted()` function with the `key` parameter to define the property to sort by.
• Utilize lambda functions for concise one-liner definitions of sorting behaviors.
• Ensure that the data structure used is compatible with the intended sort.

Mistake: Using list.sort() instead of sorted() without understanding the difference.

Solution: Use sorted() to maintain the original list order and return a new sorted list.

Mistake: Forgetting to specify the key when sorting based on properties of objects.

Solution: Always use the key parameter to sort by specific properties.