Lists & loops
Iterate, transform, and combine sequences with readable loop patterns.
How to Check if a List is Sorted in Descending Order in Python
This code defines a function that returns True if a given list is sorted in descending order, using a generator expression with all() to compare each adjacent pair.
def is_descending(lst):
"""Return True if list is sorted in descending order."""
return all(lst[i] >= lst[i + 1] for i in range(len(lst) - 1))
if __name__ == "__main__":
test_cases = [
[5, 4, 3, 2, 1],
[3, 3, 2, 1],
[1, 2, 3],
[10, 8, 9],
[]
]
for case in …How to Sort a List in Python in Ascending and Descending Order
This code demonstrates three ways to sort a list in Python: returning a new sorted list with sorted(), reversing the sort order, and sorting a list in place with the list.sort() method.
def get_sorted_data(numbers):
"""Return a new list sorted in ascending order."""
return sorted(numbers)
def reverse_sort(data):
"""Return a new list sorted in descending order."""
return sorted(data, reverse=True)
def sort_in_place(data):
"""Sort the given list in place (modifies original)."""
…How to Sort a List of Dictionaries by a Key in Python
Sort a list of dictionaries by a specified key field, optionally in descending order, using Python's built-in sorted() function.
def sort_dicts_by_key(data, key, reverse=False):
return sorted(data, key=lambda item: item.get(key), reverse=reverse)
if __name__ == "__main__":
people = [
{"name": "Alice", "age": 30},
{"name": "Bob", "age": 25},
{"name": "Charlie", "age": 35},
]
sorted_by_age = sort_dicts_b…Browse by section
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Lists & loops — Python code examples
What you will find here
This page collects lists & loops snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
Samples vs tutorials and challenges
Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.