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GeezerVison is showing github.com — learn-python/src/classes/test_class_objects.py at master · kanene/learn-python Expand file tree/ Copy pathtest_class_objects.pyMore file actions 78 lines (57 loc) · 2.75 KB / Copy pathtest_class_objects.pyFile metadata and controls78 lines (57 loc) · 2.75 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 """Class Definition Syntax. @see: https://docs.python.org/3/tutorial/classes.html#class-objects After defining the class attributes to a class, the class object can be created by assigning the object to a variable. The created object would have instance attributes associated with it. """ def test_class_objects(): """Class Objects. Class objects support two kinds of operations: - attribute references - instantiation. """ # ATTRIBUTE REFERENCES use the standard syntax used for all attribute references in # Python: obj.name. Valid attribute names are all the names that were in the class’s namespace # when the class object was created. For class MyCounter the following references are valid # attribute references: class ComplexNumber: """Example of the complex numbers class""" real = 0 imaginary = 0 def get_real(self): """Return real part of complex number.""" return self.real def get_imaginary(self): """Return imaginary part of complex number.""" return self.imaginary assert ComplexNumber.real == 0 # __doc__ is also a valid attribute, returning the docstring belonging to the class assert ComplexNumber.__doc__ == 'Example of the complex numbers class' # Class attributes can also be assigned to, so you can change the value of # ComplexNumber.counter by assignment. ComplexNumber.real = 10 assert ComplexNumber.real == 10 # CLASS INSTANTIATION uses function notation. Just pretend that the class object is a # parameterless function that returns a new instance of the class. For example # (assuming the above class): complex_number = ComplexNumber() assert complex_number.real == 10 assert complex_number.get_real() == 10 # Let's change counter default value back. ComplexNumber.real = 10 assert ComplexNumber.real == 10 # The instantiation operation (“calling” a class object) creates an empty object. Many classes # like to create objects with instances customized to a specific initial state. Therefore a # class may define a special method named __init__(), like this: class ComplexNumberWithConstructor: """Example of the class with constructor""" def __init__(self, real_part, imaginary_part): self.real = real_part self.imaginary = imaginary_part def get_real(self): """Return real part of complex number.""" return self.real def get_imaginary(self): """Return imaginary part of complex number.""" return self.imaginary complex_number = ComplexNumberWithConstructor(3.0, -4.5) assert complex_number.real, complex_number.imaginary == (3.0, -4.5) |
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