ch04

Author: adii1823

ch04/arguments.combined.py

@@ -0,0 +1,8 @@
+# arguments.combined.py
+def func(a, b, c, d, e, f):
+    print(a, b, c, d, e, f)
+
+func(1, *(2, 3), f=6, *(4, 5))
+func(*(1, 2), e=5, *(3, 4), f=6)
+func(1, **{'b': 2, 'c': 3}, d=4, **{'e': 5, 'f': 6})
+func(c=3, *(1, 2), **{'d': 4}, e=5, **{'f': 6})

ch04/arguments.keyword.py

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+# arguments.keyword.py
+def func(a, b, c):
+    print(a, b, c)
+
+func(a=1, c=2, b=3)  # prints: 1 3 2

ch04/arguments.multiple.value.py

@@ -0,0 +1,13 @@
+# arguments.multiple.value.py
+def func(a, b, c):
+    print(a, b, c)
+
+func(2, 3, a=1)
+
+"""
+$ python arguments.multiple.value.py
+Traceback (most recent call last):
+  File "arguments.multiple.value.py", line 5, in <module>
+    func(2, 3, a=1)
+TypeError: func() got multiple values for argument 'a'
+"""

ch04/arguments.positional.keyword.py

@@ -0,0 +1,15 @@
+# arguments.positional.keyword.py
+def func(a, b, c):
+    print(a, b, c)
+
+func(42, b=1, c=2)
+
+func(b=1, c=2, 42)  # positional argument after keyword arguments
+
+"""
+$ python arguments.positional.keyword.py
+  File "arguments.positional.keyword.py", line 7
+    func(b=1, c=2, 42)  # positional argument after keyword arguments
+                     ^
+SyntaxError: positional argument follows keyword argument
+"""

ch04/arguments.positional.py

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+# arguments.positional.py
+def func(a, b, c):
+    print(a, b, c)
+
+func(1, 2, 3)  # prints: 1 2 3

ch04/arguments.unpack.dict.py

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+# arguments.unpack.dict.py
+def func(a, b, c):
+    print(a, b, c)
+
+values = {'b': 1, 'c': 2, 'a': 42}
+func(**values)  # equivalent to func(b=1, c=2, a=42)

ch04/arguments.unpack.iterable.py

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+# arguments.unpack.iterable.py
+def func(a, b, c):
+    print(a, b, c)
+
+values = (1, 3, -7)
+func(*values)  # equivalent to: func(1, 3, -7)

ch04/data.science.example.py

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+# data.science.example.py
+def do_report(data_source):
+    # fetch and prepare data
+    data = fetch_data(data_source)
+    parsed_data = parse_data(data)
+    filtered_data = filter_data(parsed_data)
+    polished_data = polish_data(filtered_data)
+
+    # run algorithms on data
+    final_data = analyse(polished_data)
+
+    # create and return report
+    report = Report(final_data)
+    return report
+
+
+if __name__ == "__main__":
+
+    print(
+        "Please don't call the `do_report` function. "
+        "It's just and example."
+    )

ch04/docstrings.py

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+# docstrings.py
+def square(n):
+    """Return the square of a number n. """
+    return n ** 2
+
+def get_username(userid):
+    """Return the username of a user given their id. """
+    return db.get(user_id=userid).username
+
+
+def connect(host, port, user, password):
+    """Connect to a database.
+
+    Connect to a PostgreSQL database directly, using the given
+    parameters.
+
+    :param host: The host IP.
+    :param port: The desired port.
+    :param user: The connection username.
+    :param password: The connection password.
+    :return: The connection object.
+    """
+    # body of the function here...
+    return connection

ch04/filter.lambda.py

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+# filter.lambda.py
+def get_multiples_of_five(n):
+    return list(filter(lambda k: not k % 5, range(n)))
+
+
+print(get_multiples_of_five(50))