对于全局变量，仅使用赋值是不可能的.但是对于属性来说，它非常简单:只需使用属性(或 __getattr__/__setattr__ ).这样可以有效地将赋值转换为函数调用，使您可以添加所需的任何其他行为:

For a global variable, this is not possible using assignment alone. But for an attribute it is quite simple: just use a property (or maybe __getattr__/__setattr__). This effectively turns assignment into a function call, allowing you to add whatever additional behaviour you like:

class Foo(QWidget):
    valueChanged = pyqtSignal(object)

    def __init__(self, parent=None):
        super(Foo, self).__init__(parent)
        self._t = 0

    @property
    def t(self):
        return self._t

    @t.setter
    def t(self, value):
        self._t = value
        self.valueChanged.emit(value)

现在您可以执行foo = Foo(); foo.t = 5，并且在更改值之后将发出信号.

Now you can do foo = Foo(); foo.t = 5 and the signal will be emitted after the value has changed.