Sorting arranges collection elements according to an ordering criterion. Python provides both the list.sort() method, which changes a list in place and returns None, and the sorted() function, which returns a new list while preserving the original. section 3.3.7
Choose the operation according to how the surrounding program should handle its data:
- Use list.sort() when modifying the existing list is appropriate; pass reverse=True for descending order. section 3.3.7
- Use sorted(items) when the original order must remain available or when sorting another iterable, such as a set. section 3.3.7 section 20.3.5
- Expect numeric values to sort numerically, while mixing strings and numbers raises a TypeError. section 3.3.7
Sorting picnic arguments
A command-line program can sort its collected items only when requested: if args.sorted: items.sort(). Running ./picnic.py --sorted salad soda cupcakes produces “You are bringing cupcakes, salad, and soda.” section 3.6.2 section 3.2
$ ./picnic.py --sorted salad soda cupcakes You are bringing cupcakes, salad, and soda.
See the complete command-line result of sorting picnic items before formatting them. section 3.2
