Added a List Comprehension topic #34
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Adding additional .md file for list comprehension
Added information to list-comprehension.md
| @@ -27,6 +27,7 @@ to learn more about whatever you want after studying it. | |||
| 19. [Exceptions](exceptions.md) | |||
| 20. [Classes](classes.md) | |||
| 21. [Docstrings](docstrings.md) | |||
| 22. [List Comprehension](list-comprehension.md) | |||
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It would be good to have this immediately after loops. (You have to change the numbering.)
| # List Comprehension | ||
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| ## Definition |
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This doesn't have to be under a second title.
| ## Definition |
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| ## Definition | ||
| List comprehensions creates a new list from an existing list that is a shorter syntax than normal. It also processes the list much faster than using a for loop. |
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- "Shorter than normal" is a bit ambiguous.
- When performance matters, performance problems don't usually come from small things like this, in my experience. Not really worth mentioning.
| List comprehensions creates a new list from an existing list that is a shorter syntax than normal. It also processes the list much faster than using a for loop. | |
| List comprehensions creates a new list from an existing list using shorter syntax than loops. |
| arr = [] | ||
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| for i in animals: |
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Consider improving the variable names, e.g. arr --> filtered_animals, i --> animal, also in the list comprehension below.
| print(arr) | ||
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| ```python | ||
| ['dog', 'cat', 'ape'] |
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It would be good to show the output right at the print statement, so it is clear that it comes from print(arr). It matters more when there's multiple prints, but I think it helps here too.
| print(arr) | |
| ``` | |
| ```python | |
| ['dog', 'cat', 'ape'] | |
| print(arr) # Prints: ['dog', 'cat', 'ape'] |
| ``` | ||
| The example above does exactly the same thing but is in a much more concise syntax where it iterates through the list of animals and appends to the new list if their name is exactly 3 characters long. | ||
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| ## Syntax |
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What's the purpose of this section? Reading a description of syntax isn't a good way to learn, in my experience. It would be better to just show the i.lower() example, without trying to describe the syntax with words too much.
| - List comprehensions are a good way to shorten code | ||
| - They are versatile when it comes to iterating through iterable datasets | ||
| - Not only can you filter out data with a condition you can also change the data before it gets added to the new list | ||
| - List comprehensions normally follow: newlist = [**expression** for **item** in **iterable** if **condition**] |
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Add . to the end of each. Also consider removing the last item, if you remove the ## Syntax section.
list-comprehension.md
Taking a class on github and I had to contribute to a repository. So I thought contributing to a python-tutorial would be interesting. I can add or change more things if needed.