From d333a777aff579ac9d4f38467345fb946dd46bc3 Mon Sep 17 00:00:00 2001 From: swfarnsworth Date: Sat, 6 Feb 2021 10:35:27 -0500 Subject: New example to emphasize the mapping functionality rather than filtering. Previously, the example only conveyed how the `if` statement of list comps could be used to filter a list, whereas the mapping functionality is what people primarily use list comps for. --- bot/resources/tags/listcomps.md | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/bot/resources/tags/listcomps.md b/bot/resources/tags/listcomps.md index 0003b9bb8..ba00a4bf7 100644 --- a/bot/resources/tags/listcomps.md +++ b/bot/resources/tags/listcomps.md @@ -1,14 +1,19 @@ -Do you ever find yourself writing something like: +Do you ever find yourself writing something like this? ```py -even_numbers = [] -for n in range(20): - if n % 2 == 0: - even_numbers.append(n) +>>> squares = [] +>>> for n in range(5): +... squares.append(n ** 2) +[0, 1, 4, 9, 16] ``` -Using list comprehensions can simplify this significantly, and greatly improve code readability. If we rewrite the example above to use list comprehensions, it would look like this: +Using list comprehensions can make this both shorter and more readable. As a list comprehension, the same code would look like this: ```py -even_numbers = [n for n in range(20) if n % 2 == 0] +>>> [n ** 2 for n in range(5)] +[0, 1, 4, 9, 16] +``` +List comprehensions also get an `if` statement: +```python +>>> [n ** 2 for n in range(5) if n % 2 == 0] +[0, 4, 16] ``` -This also works for generators, dicts and sets by using `()` or `{}` instead of `[]`. -For more info, see [this pythonforbeginners.com post](http://www.pythonforbeginners.com/basics/list-comprehensions-in-python) or [PEP 202](https://www.python.org/dev/peps/pep-0202/). +For more info, see [this pythonforbeginners.com post](http://www.pythonforbeginners.com/basics/list-comprehensions-in-python). -- cgit v1.2.3