Merge pull request #597 from realpython/python-dict-comprehension

Sample code for the article on dict comprehension

python-dict-comprehension/README.md

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+# Python Dictionary Comprehensions: How and When to Use Them
+
+This folder provides the code examples for the Real Python tutorial [Python Dictionary Comprehensions: How and When to Use Them](https://realpython.com/python-dictionary-comprehension/).

python-dict-comprehension/computer_parts_v1.py

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+parts = [
+    "CPU",
+    "GPU",
+    "Motherboard",
+    "RAM",
+    "SSD",
+    "Power Supply",
+    "Case",
+    "Cooling Fan",
+]
+stocks = [15, 8, 12, 30, 25, 10, 5, 20]
+print({part: stock for part, stock in zip(parts, stocks)})

python-dict-comprehension/computer_parts_v2.py

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+parts = [
+    "CPU",
+    "GPU",
+    "Motherboard",
+    "RAM",
+    "SSD",
+    "Power Supply",
+    "Case",
+    "Cooling Fan",
+]
+stocks = [15, 8, 12, 30, 25, 10, 5, 20]
+part_costs = [250, 500, 150, 80, 100, 120, 70, 25]
+print(
+    {
+        part: stock * cost
+        for part, stock, cost in zip(parts, stocks, part_costs)
+    }
+)

python-dict-comprehension/contructor.py

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+print(dict(apple=0.40, orange=0.35, banana=0.25))

python-dict-comprehension/filter_keys.py

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+codes = {
+    "1001": "Townsville",
+    "1002": "Lakeview",
+    "1003": "Mountainview",
+    "1101": "Riverside",
+    "1102": "Hilltop",
+    "1201": "Greenfield",
+    "1202": "Sunnydale",
+    "1301": "Meadowbrook",
+    "1302": "Creekwood",
+}
+print({code: town for code, town in codes.items() if "1100" <= code <= "1300"})

python-dict-comprehension/filter_values.py

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+numbers = {"one": 1, "two": 2, "three": 3, "four": 4, "five": 5}
+print({key: value for key, value in numbers.items() if value % 2 == 0})

python-dict-comprehension/fruits_v1.py

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+fruits = ["apple", "banana", "cherry"]
+print({fruit.upper(): len(fruit) for fruit in fruits})

python-dict-comprehension/fruits_v2.py

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+fruits = {
+    "apple": 1.00,
+    "banana": 0.50,
+    "cherry": 2.00,
+}
+print({fruit: round(price * 0.95, 2) for fruit, price in fruits.items()})

python-dict-comprehension/fruits_v3.py

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+fruits = {"apple": 1.0, "banana": 0.5, "cherry": 2.0, "mango": 2.3}
+with_discount = ["apple", "cherry"]
+print(
+    {
+        fruit: price * 0.9 if fruit in with_discount else price
+        for fruit, price in fruits.items()
+    }
+)

python-dict-comprehension/letters.py

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+from string import ascii_lowercase
+
+print({letter: ord(letter) for letter in ascii_lowercase})

python-dict-comprehension/likes.py

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+likes = {"color": "blue", "fruit": "apple", "pet": "dog"}
+print(likes)
+likes["hobby"] = "guitar"
+print(likes)

python-dict-comprehension/nested_for.py

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+matrix = [
+    [9, 3, 8, 3],
+    [4, 5, 2, 8],
+    [6, 4, 3, 1],
+    [1, 0, 4, 5],
+]
+print({value: value**2 for row in matrix for value in row})

python-dict-comprehension/powers_of_two_v1.py

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+powers_of_two = {}
+
+for integer in range(1, 10):
+    powers_of_two[integer] = 2**integer
+
+print(powers_of_two)

python-dict-comprehension/powers_of_two_v2.py

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+power_of_two = {integer: 2**integer for integer in range(1, 10)}
+print(power_of_two)

python-dict-comprehension/swap_key_value.py

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+parts = {
+    "CPU": 10021,
+    "GPU": 10022,
+    "Motherboard": 10023,
+    "RAM": 10024,
+    "SSD": 10025,
+    "Power Supply": 10027,
+    "Case": 10026,
+    "Cooling Fan": 10025,
+}
+print({value: key for key, value in parts.items()})