76 lines
2.5 KiB
Python
76 lines
2.5 KiB
Python
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"""This is a sample module.
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It defines three functions average(), average_evens(), and average_odds().
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The point is to show how we can put Python code in a .py file to be re-used
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in some other place.
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We should never forget to document the code as well, both on the module
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level (i.e., this docstring) but also in every function it defines.
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When imported, Python modules are executed top to bottom before the flow of
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execution returns to wherever they were imported into.
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An important convention is to prefix variables and functions that are not to
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be used outside the module with a single underscore "_". This way, we can
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design the code within a module in a modular fashion and only "export" what we
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want.
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Here, all three functions internally forward the computation to an internal
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utility function _scaled_average() that contains all the logic common to the
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three functions. Also, we define one _default_scalar variable that is used as
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the default for the scalar parameter in each of the functions.
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While this example is stylized, it shows how Python modules are often
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designed.
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"""
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_default_scalar = 1
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def _scaled_average(numbers, scalar):
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"""Internal utility function to calculate scaled averages."""
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average = sum(numbers) / len(numbers)
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return scalar * average
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def average(numbers, *, scalar=_default_scalar):
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"""Calculate the average of all numbers in a list.
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Args:
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numbers (list): list of numbers; may be integers or floats
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scalar (float, optional): the scalar that multiplies the
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average of the even numbers
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Returns:
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float: (scaled) average
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"""
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return _scaled_average(numbers, scalar)
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def average_evens(numbers, *, scalar=_default_scalar):
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"""Calculate the average of all even numbers in a list.
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Args:
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numbers (list): list of numbers; may be integers or floats
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scalar (float, optional): the scalar that multiplies the
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average of the even numbers
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Returns:
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float: (scaled) average
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"""
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return _scaled_average([n for n in numbers if n % 2 == 0], scalar)
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def average_odds(numbers, *, scalar=_default_scalar):
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"""Calculate the average of all odd numbers in a list.
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Args:
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numbers (list): list of numbers; may be integers or floats
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scalar (float, optional): the scalar that multiplies the
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average of the even numbers
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Returns:
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float: (scaled) average
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"""
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return _scaled_average([n for n in numbers if n % 2 != 0], scalar)
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