subclass

问题 When I call a method that was overrided from my constructor, I am getting an error and it says that it is missing an argument (due to the subclass requiring a second argument). However, I called the method in the super(), so why doesn't it call the super class version of that method? This is best illustrated with a short example: class A: def __init__(self): self.do() def do(self): print("A") class B(A): def __init__(self): super().__init__() self.do("B") def do(self, arg2): super().do()

问题 I added two handlers with different formatters to my logger. The first one requires subclassing logging.Formatter to do custom formatting. The default formatter will suffice for the second handler. Let's say the first formatter simply removes newline characters from the message. The following script illustrates what seems like strange behavior: import logging logger = logging.getLogger(__name__) class CustomFormatter(logging.Formatter): def __init__(self, *args, **kwargs): super().__init__(

问题 I have answered my own question - see answer below I'm writing a class, and I want this behavior: a = f(10,20) some_funct(a.row) # some_function is given 10 some_funct(a.col) # some_function is given 20 some_funct(a) # some_function is given a tuple of 10, 20 <-- THIS ONE :) The last behavior is stumping me. I have not seen any examples that cover this. Thus far: class f(object): """Simple 2d object""" row: int col: int def __init__(self, row, col): self.row = row self.col = col Explictly I

问题 I have answered my own question - see answer below I'm writing a class, and I want this behavior: a = f(10,20) some_funct(a.row) # some_function is given 10 some_funct(a.col) # some_function is given 20 some_funct(a) # some_function is given a tuple of 10, 20 <-- THIS ONE :) The last behavior is stumping me. I have not seen any examples that cover this. Thus far: class f(object): """Simple 2d object""" row: int col: int def __init__(self, row, col): self.row = row self.col = col Explictly I

问题 A little background: There are three classes involved: Tester(main method) , DNASequence(object) and ProteinDNA(subclass of DNASequence) . All three are under the same package. The constructor for ProteinDNA accepts an object DNASequence and an integer public class ProteinDNA extends DNASequence{ public ProteinDNA(DNASequence dna, int startAt){ //this is the constructor Compiling the class ProteinDNA gives me an error at the constructor. The error in Eclipse is: "Implicit super constructor

问题 I found a great post on SO that seems to be exactly what I want: Is it possible to access a parent property from a child that is in a collection? However my adaptation of it is giving me Object doesn't support this property or method. My code which now works thanks to Mat's Mug and Tomalak: Parent Class - clsComputer Option Explicit Private pCD As clsCD '''''''''''''''''''''''''''''' ' CD property '''''''''''''''''''''''''''''' Public Property Get CD() As clsCD If pCD Is Nothing Then Set pCD

问题 I would like to persist inner class into database. But it dosnt work. Is there possibilty to do that? Or should i put that inner class into new plain file? Now I am getting an error [IllegalArgumentException: Unknown entity: models.foo$bar] My class file: package models; public class foo { @Required public String report; @Required public String reportType; @Entity public static class bar{ @Required public int year; @Required public int month; public void toDataBase() { JPA.em().persist(this);

问题 I would like to persist inner class into database. But it dosnt work. Is there possibilty to do that? Or should i put that inner class into new plain file? Now I am getting an error [IllegalArgumentException: Unknown entity: models.foo$bar] My class file: package models; public class foo { @Required public String report; @Required public String reportType; @Entity public static class bar{ @Required public int year; @Required public int month; public void toDataBase() { JPA.em().persist(this);

问题 This... class A(object): class B(A): def __init__(self): pass ... throws "NameError: name 'A' is not defined". Is there proper syntax to accomplish this, or must I use workarounds, like this? class A(object): pass class _B(A): pass A.B = _B The prior is strongly preferable. Thank you. 回答1: As per OPs request, posting as an answer. That's an inner class, not a subclass. No, an inner class can't inherit (not extend) its outer class because the outer class is not fully defined while defining the

问题 I'm trying to assign a sub class object array to its super class. The program compiles successfully, but I' getting an ArrayStoreException . I know that arrays parent and child are references to same array, but shouldn't I be able to access method func at least? class Pclass { Pclass() { System.out.println("constructor : Parent class"); } public void func() { System.out.println("Parent class"); } } class Cclass extends Pclass { Cclass() { System.out.println("Constructor : Child class"); }