properties

来源： https://stackoverflow.com/questions/48778945/by-design-should-a-property-getter-ever-throw-an-exception-in-python

来源： https://stackoverflow.com/questions/48778945/by-design-should-a-property-getter-ever-throw-an-exception-in-python

来源： https://stackoverflow.com/questions/45780772/can-we-use-willset-and-didset-with-getter-and-setter

来源： https://stackoverflow.com/questions/45780772/can-we-use-willset-and-didset-with-getter-and-setter

问题 I am running through a react tutorial on tutsplus that is a bit old, and the code doesn't work as it was originally written. I actually am totally ok with this as it forces me to learn more independently, however I have spent a while on a bug that I just can't figure out. The bug consists of not being able to pass on an objects key, which prevents my program from updating the state of the correct object. First off here is the repo if you want to run this code and see it in action: https:/

问题 I am running through a react tutorial on tutsplus that is a bit old, and the code doesn't work as it was originally written. I actually am totally ok with this as it forces me to learn more independently, however I have spent a while on a bug that I just can't figure out. The bug consists of not being able to pass on an objects key, which prevents my program from updating the state of the correct object. First off here is the repo if you want to run this code and see it in action: https:/

问题 This question already has answers here : What is the difference between a field and a property? (32 answers) Closed 13 days ago . What are the pros and cons of expression-bodied properties vs straight property declarations? For example, is there any advantage to using; public string Foo => "Bar" vs simply public string Foo = "Bar" My understanding was the => is used when the value comes from a method, like a lambda function. If the value is a primitive like a string or int, why would anyone

问题 When my application starts it reads a configuration properties file using the following code: Properties properties = new Properties(); // parse the config resource try (InputStream input = getClass().getClassLoader().getResourceAsStream(filename)) { if (input == null) { // throw exception } // read the property list (key-value pairs) from the input byte stream properties.load(input); } I am able to read and set individual properties. The properties file is located in src/main/resources and

问题 Situation Similar to this question, I want to replace a property. Unlike that question, I do not want to override it in a sub-class. I want to replace it in the init and in the property itself for efficiency, so that it doesn't have to call a function which calculates the value each time the property is called. I have a class which has a property on it. The constructor may take the value of the property. If it is passed the value, I want to replace the property with the value (not just set

问题 Given: def test_to_check_exception_is_thrown(self): # Arrange c = Class() # Act and Assert self.assertRaises(NameError, c.do_something) If do_something throws an exception the test passes. But I have a property, and when I replace c.do_something with c.name = "Name" I get an error about my Test Module not being imported and Eclipse highlights the equals symbol. How do I test a property throws an exception? Edit: setattr and getattr are new to me. They've certainly helped in this case, thanks.