114 lines
1.9 KiB
Python
114 lines
1.9 KiB
Python
# test builtin property
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try:
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property
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except:
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print("SKIP")
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raise SystemExit
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# create a property object explicitly
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property()
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property(1, 2, 3)
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# use its accessor methods
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p = property()
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p.getter(1)
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p.setter(2)
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p.deleter(3)
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# basic use as a decorator
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class A:
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def __init__(self, x):
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self._x = x
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@property
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def x(self):
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print("x get")
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return self._x
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a = A(1)
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print(a.x)
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try:
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a.x = 2
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except AttributeError:
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print("AttributeError")
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# explicit use within a class
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class B:
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def __init__(self, x):
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self._x = x
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def xget(self):
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print("x get")
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return self._x
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def xset(self, value):
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print("x set")
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self._x = value
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def xdel(self):
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print("x del")
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x = property(xget, xset, xdel)
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b = B(3)
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print(b.x)
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b.x = 4
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print(b.x)
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del b.x
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# full use as a decorator
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class C:
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def __init__(self, x):
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self._x = x
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@property
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def x(self):
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print("x get")
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return self._x
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@x.setter
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def x(self, value):
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print("x set")
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self._x = value
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@x.deleter
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def x(self):
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print("x del")
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c = C(5)
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print(c.x)
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c.x = 6
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print(c.x)
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del c.x
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# a property that has no get, set or del
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class D:
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prop = property()
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d = D()
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try:
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d.prop
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except AttributeError:
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print('AttributeError')
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try:
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d.prop = 1
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except AttributeError:
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print('AttributeError')
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try:
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del d.prop
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except AttributeError:
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print('AttributeError')
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# properties take keyword arguments
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class E:
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p = property(lambda self: 42, doc="This is truth.")
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# not tested for because the other keyword arguments are not accepted
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# q = property(fget=lambda self: 21, doc="Half the truth.")
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print(E().p)
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# a property as an instance member should not be delegated to
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class F:
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def __init__(self):
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self.prop_member = property()
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print(type(F().prop_member))
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