Merge pull request #486 from realpython/list-comprehension-update

Add materials for the list comprehension update

Author: KateFinegan

python-list-comprehension/README.md

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+# When to Use a List Comprehension in Python
+
+This repository holds the code for Real Python's [When to Use a List Comprehension in Python](https://realpython.com/list-comprehension-python) tutorial.
+
+## License
+
+Distributed under the MIT license. See [`LICENSE`](../LICENSE) for more information.

python-list-comprehension/dict_comprehension.py

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+quote = "life, uh, finds a way"
+unique_vowels = {char for char in quote if char in "aeiou"}
+print(unique_vowels)

python-list-comprehension/for_loop.py

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+squares = []
+for i in range(10):
+    squares.append(i * i)
+print(squares)

python-list-comprehension/list_comprehension.py

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+squares = [i * i for i in range(10)]
+print(squares)

python-list-comprehension/list_comprehension_with_assignment_operator.py

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+import random
+
+
+def get_weather_data():
+    return random.randrange(90, 110)
+
+
+hot_temps = [temp for _ in range(20) if (temp := get_weather_data()) >= 100]
+print(hot_temps)

python-list-comprehension/list_comprehension_with_condition.py

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+sentence = "the rocket came back from mars"
+vowels = [char for char in sentence if char in "aeiou"]
+print(vowels)

python-list-comprehension/list_comprehension_with_condition_and_function.py

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+sentence = "The rocket, who was named Ted, came back \
+from Mars because he missed his friends."
+
+
+def is_consonant(letter):
+    vowels = "aeiou"
+    return letter.isalpha() and letter.lower() not in vowels
+
+
+consonants = [char for char in sentence if is_consonant(char)]
+print(consonants)

python-list-comprehension/list_comprehension_with_function.py

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+prices = [1.09, 23.56, 57.84, 4.56, 6.78]
+TAX_RATE = 0.08
+
+
+def get_price_with_tax(price):
+    return price * (1 + TAX_RATE)
+
+
+final_prices = [get_price_with_tax(price) for price in prices]
+print(final_prices)

python-list-comprehension/map.py

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+prices = [1.09, 23.56, 57.84, 4.56, 6.78]
+TAX_RATE = 0.08
+
+
+def get_price_with_tax(price):
+    return price * (1 + TAX_RATE)
+
+
+final_prices = map(get_price_with_tax, prices)
+print(list(final_prices))

python-list-comprehension/profiling.py

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+import random
+import timeit
+
+TAX_RATE = 0.08
+prices = [random.randrange(100) for _ in range(100000)]
+
+
+def get_price(price):
+    return price * (1 + TAX_RATE)
+
+
+def get_prices_with_map():
+    return list(map(get_price, prices))
+
+
+def get_prices_with_comprehension():
+    return [get_price(price) for price in prices]
+
+
+def get_prices_with_loop():
+    prices = []
+    for price in prices:
+        prices.append(get_price(price))
+    return prices
+
+
+print(timeit.timeit(get_prices_with_map, number=100))
+print(timeit.timeit(get_prices_with_comprehension, number=100))
+print(timeit.timeit(get_prices_with_loop, number=100))