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There is a property syntax in Python, which is similar to C#'s get set syntax. Its functions have the following two points:
Set class methods as read-only properties;
Implement properties getter and setter methods;
The following focuses on these two points:
Set the class method as a read-only attribute
Please read the following code first
class Book(object): def __init__(self, title, author, pub_date): self.title = title self.author = author self.pub_date = pub_date @property def des_message(self): return u'书名:%s, 作者:%s, 出版日期:%s' % (self.title, self.author, self.pub_date)
In this code, use property as a decorator to modify the des_message function. Its function is to turn the function des_message into a property of the class, and it is read-only. The effect is as follows:
#As shown in the figure above, the method becomes a property, which can be accessed by accessing properties. But if you modify its value, an AttributeError error will be reported. It is read-only
Implement the getter and setter methods of the attribute
Then check the following code:
class Array(object): def __init__(self, length=0, base_index=0): assert length >= 0 self._data = [None for i in xrange(length)] self._base_index = base_index def get_base_index(self): return self._base_index def set_base_index(self, base_index): self._base_index = base_index base_index = property( fget=lambda self: self.get_base_index(), fset=lambda self, value: self.set_base_index(value) )
Here We set a base_index attribute for class Array, which uses property to implement the fget and fset functions of base_index. base_index is readable and writable. The effect is as follows:
As shown above As shown, base_index is readable and writable.
Finally
property is a good syntax feature of Python, and we should use it frequently in programming.
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