Merge pull request #675 from realpython/python-scope-legb-rule

Sample code for the article on scope

Author: brendaweles

python-scope-legb-rule/README.md

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+# Python Scope and the LEGB Rule: Resolving Names in Your Code
+
+This folder provides the code examples for the Real Python tutorial [Python Scope and the LEGB Rule: Resolving Names in Your Code](https://realpython.com/python-scope-legb-rule/).

python-scope-legb-rule/calculations.py

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+def square(base):
+    result = base**2
+    print(f"The square of {base} is: {result}")
+
+
+def cube(base):
+    result = base**3
+    print(dir())
+    print(vars())
+    print(f"The cube of {base} is: {result}")

python-scope-legb-rule/counter.py

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+counter = 0  # A global name
+
+
+def update_counter_v1():
+    global counter  # Declares counter as global
+    counter = counter + 1  # Successfully updates the counter
+
+
+def update_counter_v2(counter):
+    return counter + 1  # Relies on a local name

python-scope-legb-rule/dispatch.py

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+from sys import platform
+
+
+def linux_print():
+    print("Printing from Linux...")
+
+
+def win32_print():
+    print("Printing from Windows...")
+
+
+def darwin_print():
+    print("Printing from macOS...")
+
+
+printer = globals()[platform + "_print"]
+
+printer()

python-scope-legb-rule/exception_variable.py

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+numbers = [1, 2, 3]
+
+try:
+    numbers[4]
+except IndexError as error:
+    # The variable error is local to this block
+    exception = error
+    error
+
+
+print(exception)

python-scope-legb-rule/lazy_global.py

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+def create_lazy_name():
+    global number  # Create a global name lazily
+    number = 42
+    return number
+
+
+create_lazy_name()
+print(number)

python-scope-legb-rule/nested_function.py

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+def outer_func():
+    variable = 100
+
+    def inner_func():
+        print(f"Printing variable from inner_func(): {variable}")
+
+    inner_func()
+    print(f"Printing variable from outer_func(): {variable}")
+
+
+outer_func()

python-scope-legb-rule/power_factory.py

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+def power_factory(exponent):
+    def power(base):
+        return base**exponent
+
+    return power
+
+
+square = power_factory(2)
+print(square(10))
+
+cube = power_factory(3)
+print(cube(10))