Merge pull request #351 from realpython/python-assignment-statements

Sample code for the assignment statements article

Author: KateFinegan

python-assignment-statements/README.md

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+# Python's Assignment Operator: Write Robust Assignments
+
+This folder provides the code examples for the tutorial [Python's Assignment Operator: Write Robust Assignments](https://realpython.com/python-assignment-operator/).

python-assignment-statements/bsort.py

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+def bubble_sort_list(a_list):
+    n = len(a_list)
+    for i in range(n):
+        is_sorted = True
+        for j in range(n - i - 1):
+            if a_list[j] > a_list[j + 1]:
+                a_list[j], a_list[j + 1] = a_list[j + 1], a_list[j]
+                is_sorted = False
+        if is_sorted:
+            break
+    return a_list

python-assignment-statements/equation.py

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+from math import sqrt
+
+a, b, c = 2.0, -1.0, -4.0
+
+x1, x2 = (
+    (-b - sqrt(b**2 - 4 * a * c)) / (2 * a),
+    (-b + sqrt(b**2 - 4 * a * c)) / (2 * a),
+)
+
+print(f"{x1=}, {x2=}")

python-assignment-statements/hello.py

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+with open("hello.txt", mode="r") as hello:
+    print(f"File object: {hello}")
+    print(f"Memory address: {id(hello)}")
+    print("File content:")
+    for line in hello:
+        print("> ", line)

python-assignment-statements/hello.txt

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+Hello, Pythonista!
+Welcome to Real Python!

python-assignment-statements/interning.py

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+from platform import python_version
+
+interning = [x for x, y in zip(range(-10, 500), range(-10, 500)) if x is y]
+
+print(
+    f"Interning interval for Python {python_version()} is:"
+    f" ({interning[0]} to {interning[-1]})"
+)

python-assignment-statements/mean.py

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+# def mean(sample):
+#     n = len(sample)
+#     if n == 0:
+#         raise ValueError("input data required")
+#     return sum(sample) / n
+
+
+def mean(sample):
+    if (n := len(sample)) == 0:
+        raise ValueError("input data required")
+    return sum(sample) / n

python-assignment-statements/point.py

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+class Point:
+    @property
+    def x(self):
+        return self._x
+
+    @x.setter
+    def x(self, value):
+        try:
+            self._x = float(value)
+        except ValueError:
+            raise ValueError('"x" must be a number') from None
+
+    @property
+    def y(self):
+        return self._y
+
+    @y.setter
+    def y(self, value):
+        try:
+            self._y = float(value)
+        except ValueError:
+            raise ValueError('"y" must be a number') from None

python-assignment-statements/point_descriptor.py

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+class Coordinate:
+    def __set_name__(self, owner, name):
+        self._name = name
+
+    def __get__(self, instance, owner):
+        return instance.__dict__[self._name]
+
+    def __set__(self, instance, value):
+        try:
+            instance.__dict__[self._name] = float(value)
+        except ValueError:
+            raise ValueError(f'"{self._name}" must be a number') from None
+
+
+class Point:
+    x = Coordinate()
+    y = Coordinate()

python-assignment-statements/reverse.py

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+def custom_reverse(sequence):
+    index = len(sequence) - 1
+    while index >= 0:
+        yield sequence[index]
+        index -= 1