Master Python’s sorted() Function: Simple to Advanced Sorting Techniques

1. Introduction

A follower asked about sorting in Python, so this article shares how to use the built‑in sorted() function for everyday tasks.

2. Basic Usage

The sorted() function can sort a simple list in ascending order.

lst = [3, 28, 18, 29, 2, 5, 88]
result = sorted(lst)
print(result)

Result: [2, 3, 5, 18, 28, 29, 88].

To sort in descending order, add the reverse=True argument.

lst = [3, 28, 18, 29, 2, 5, 88]
result = sorted(lst, reverse=True)
print(result)

Result: [88, 29, 28, 18, 5, 3, 2].

3. Advanced Usage

When sorting more complex iterables such as a list of dictionaries, provide a custom key function.

lst = [
    {"id": 1, "name": "鲁班", "age": 18},
    {"id": 2, "name": "鲁班大师", "age": 26},
    {"id": 3, "name": "鲁大师", "age": 23},
    {"id": 4, "name": "狄仁杰", "age": 48}
]
# Sort by age in ascending order
sorted(lst, key=lambda x: x.get('age'))

The sorted() function accepts three parameters: the iterable, a key function that determines the sort order, and a reverse flag (True for descending, False for ascending).

To extract items with age greater than or equal to 28, combine filter() with a lambda:

list(filter(lambda x: x['age'] >= 28, lst))

4. Bonus: Deep and Shallow Copy

Additional notes on Python’s deep and shallow copy mechanisms are often asked in interviews and are useful for handling mutable objects.