大约有 40,000 项符合查询结果（耗时：0.0232秒） [XML]
Python (and Python C API): __new__ versus __init__
...vs immutable types.
__new__ accepts a type as the first argument, and (usually) returns a new instance of that type. Thus it is suitable for use with both mutable and immutable types.
__init__ accepts an instance as the first argument and modifies the attributes of that instance. This is inappropr...
Django: How to completely uninstall a Django app?
What is the procedure for completely uninstalling a Django app, complete with database removal?
5 Answers
...
Understanding Python super() with __init__() methods [duplicate]
...can be nice. But the main advantage comes with multiple inheritance, where all sorts of fun stuff can happen. See the standard docs on super if you haven't already.
Note that the syntax changed in Python 3.0: you can just say super().__init__() instead of super(ChildB, self).__init__() which IMO is...
MVVM in WPF - How to alert ViewModel of changes in Model… or should I?
...
RaisePropertyChanged("ViewModelCopyOfSomeProperty");
}
But typically this is only needed if more than one object will be making changes to the Model's data, which is not usually the case.
If you ever have a case where you don't actually have a reference to your Model property to attach t...
Method Resolution Order (MRO) in new-style classes?
...ject'>)
with A forced to come in resolution order only once and after all of its subclasses, so that overrides (i.e., C's override of member x) actually work sensibly.
It's one of the reasons that old-style classes should be avoided: multiple inheritance with "diamond-like" patterns just doesn...
Or versus OrElse
...oth terms. When temp Is DBNull.Value, it can't be compared to zero, so it falls over.
You should use... well, whichever one makes sense.
share
|
improve this answer
|
follow...
What is the purpose of the single underscore “_” variable in Python?
...cate that part
of a function result is being deliberately ignored (Conceptually, it is being discarded.), as in code like:
label, has_label, _ = text.partition(':').
As part of a function definition (using either def or lambda), where
the signature is fixed (e.g. by a callback or parent class API), ...
What is the purpose of class methods?
...sson was that Python is not Java , and so I've just spent a while turning all my Class methods into functions.
17 Answers
...
What is the difference between join and merge in Pandas?
...
pandas.merge() is the underlying function used for all merge/join behavior.
DataFrames provide the pandas.DataFrame.merge() and pandas.DataFrame.join() methods as a convenient way to access the capabilities of pandas.merge(). For example, df1.merge(right=df2, ...) is equiva...
Get a filtered list of files in a directory
...t a list of files in a directory using Python, but I do not want a list of ALL the files.
14 Answers
...