Merge pull request #417 from realpython/working-with-the-python-operator-module

Add code for operators tutorial

Author: KateFinegan

python-operator-module/README.md

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+# Working With the Python operator Module
+
+This folder contains supplementary code for the Real Python tutorial on [Working With the Python operator Module](https://realpython.com/python-operator-module/). You can copy the code examples, or continue your learning by experimenting more with them.
+
+## Setup
+
+For most of the examples, you'll use the `operator`, `pickle`, `dataclasses`, and `timeit` modules.  All of these come built in to Python. No additional installation is necessary.
+
+## Usage
+
+You can run each individual file with your local Python interpreter:
+
+```bash
+$ python filename.py
+```
+
+You can find more information and context on the code blocks in [Working With the Python operator Module](https://realpython.com/python-operator-module/).

python-operator-module/attrgetter_min_max.py

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+import operator
+from dataclasses import dataclass
+
+
+@dataclass
+class Musician:
+    id: int
+    fname: str
+    lname: str
+    group: str
+
+
+musician_lists = [
+    [1, "Brian", "Wilson", "Beach Boys"],
+    [2, "Carl", "Wilson", "Beach Boys"],
+    [3, "Dennis", "Wilson", "Beach Boys"],
+    [4, "Bruce", "Johnston", "Beach Boys"],
+    [5, "Hank", "Marvin", "Shadows"],
+    [6, "Bruce", "Welch", "Shadows"],
+    [7, "Brian", "Bennett", "Shadows"],
+]
+
+group_members = []
+
+for musician in musician_lists:
+    group_members.append(Musician(*musician))
+
+get_id = operator.attrgetter("id")
+
+print(min(group_members, key=get_id))
+print(max(group_members, key=get_id))

python-operator-module/attrgetter_selecting.py

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+import operator
+from dataclasses import dataclass
+
+
+@dataclass
+class Musician:
+    id: int
+    fname: str
+    lname: str
+    group: str
+
+
+musician_lists = [
+    [1, "Brian", "Wilson", "Beach Boys"],
+    [2, "Carl", "Wilson", "Beach Boys"],
+    [3, "Dennis", "Wilson", "Beach Boys"],
+    [4, "Bruce", "Johnston", "Beach Boys"],
+    [5, "Hank", "Marvin", "Shadows"],
+    [6, "Bruce", "Welch", "Shadows"],
+    [7, "Brian", "Bennett", "Shadows"],
+]
+
+group_members = []
+
+for musician in musician_lists:
+    group_members.append(Musician(*musician))
+
+# Returning a single attribute.
+get_fname = operator.attrgetter("fname")
+
+for person in group_members:
+    print(get_fname(person))
+
+# Returning multiple attributes.
+get_id_lname = operator.attrgetter("id", "lname")
+
+for person in group_members:
+    print(get_id_lname(person))

python-operator-module/attrgetter_sorting.py

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+import operator
+from dataclasses import dataclass
+
+
+@dataclass
+class Musician:
+    id: int
+    fname: str
+    lname: str
+    group: str
+
+
+musician_lists = [
+    [1, "Brian", "Wilson", "Beach Boys"],
+    [2, "Carl", "Wilson", "Beach Boys"],
+    [3, "Dennis", "Wilson", "Beach Boys"],
+    [4, "Bruce", "Johnston", "Beach Boys"],
+    [5, "Hank", "Marvin", "Shadows"],
+    [6, "Bruce", "Welch", "Shadows"],
+    [7, "Brian", "Bennett", "Shadows"],
+]
+
+group_members = []
+
+for musician in musician_lists:
+    group_members.append(Musician(*musician))
+
+# Sorting on a single attribute.
+
+get_id = operator.attrgetter("id")
+for musician in sorted(group_members, key=get_id, reverse=True):
+    print(musician)

python-operator-module/calculate_modulus.pkl

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+# Deserialize the function unsuccessfully.
+
+import pickle
+
+with open("calculate_modulus.pkl", "rb") as f:
+    unpickled_modulus = pickle.load(f)
+
+print(unpickled_modulus(7, 4))

python-operator-module/calculate_modulus_deserialize_failed.py

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+# Deserialize the function successfully.
+
+import pickle
+
+
+def calculate_modulus(operand1, operand2):
+    return operand1 % operand2
+
+
+with open("calculate_modulus.pkl", "rb") as f:
+    unpickled_modulus = pickle.load(f)
+
+print(unpickled_modulus(7, 4))

python-operator-module/calculate_modulus_deserialize_fixed.py

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+import pickle
+
+
+def calculate_modulus(operand1, operand2):
+    return operand1 % operand2
+
+
+print(calculate_modulus(7, 4))
+
+
+with open("calculate_modulus.pkl", "wb") as f:
+    pickle.dump(calculate_modulus, f)
+
+# Deserialize the function.
+
+with open("calculate_modulus.pkl", "rb") as f:
+    unpickled_modulus = pickle.load(f)
+
+print(unpickled_modulus(7, 4))

python-operator-module/calculate_modulus_serialize_deserialize.py

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+import operator
+
+musician_dicts = [
+    {"id": 1, "fname": "Brian", "lname": "Wilson", "group": "Beach Boys"},
+    {"id": 2, "fname": "Carl", "lname": "Wilson", "group": "Beach Boys"},
+    {"id": 3, "fname": "Dennis", "lname": "Wilson", "group": "Beach Boys"},
+    {"id": 4, "fname": "Bruce", "lname": "Johnston", "group": "Beach Boys"},
+    {"id": 5, "fname": "Hank", "lname": "Marvin", "group": "Shadows"},
+    {"id": 6, "fname": "Bruce", "lname": "Welch", "group": "Shadows"},
+    {"id": 7, "fname": "Brian", "lname": "Bennett", "group": "Shadows"},
+]
+
+
+# Get a single element
+get_element_four = operator.itemgetter(4)
+print(get_element_four(musician_dicts))
+
+# Get multiple elements
+get_elements_one_three_five = operator.itemgetter(1, 3, 5)
+print(get_elements_one_three_five(musician_dicts))
+
+# Get values within elements
+get_names = operator.itemgetter("fname", "lname")
+
+for musician in get_elements_one_three_five(musician_dicts):
+    print(get_names(musician))

python-operator-module/itemgetter_from_dictionary.py

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+import operator
+
+musician_lists = [
+    [1, "Brian", "Wilson", "Beach Boys"],
+    [2, "Carl", "Wilson", "Beach Boys"],
+    [3, "Dennis", "Wilson", "Beach Boys"],
+    [4, "Bruce", "Johnston", "Beach Boys"],
+    [5, "Hank", "Marvin", "Shadows"],
+    [6, "Bruce", "Welch", "Shadows"],
+    [7, "Brian", "Bennett", "Shadows"],
+]
+
+get_id = operator.itemgetter(0)
+
+print(max(musician_lists, key=get_id))
+
+print(min(musician_lists, key=get_id))