大约有 40,000 项符合查询结果（耗时：0.0730秒） [XML]
What's the difference between django OneToOneField and ForeignKey?
...Guide to Django:
OneToOneField
A one-to-one relationship. Conceptually, this is similar to a ForeignKey with unique=True, but the "reverse" side of the relation will directly return a single object.
In contrast to the OneToOneField "reverse" relation, a ForeignKey "reverse" relation retur...
What is the proper way to comment functions in Python?
Is there a generally accepted way to comment functions in Python? Is the following acceptable?
10 Answers
...
How to list all installed packages and their versions in Python?
Is there a way in Python to list all installed packages and their versions?
11 Answers
...
How to change the CHARACTER SET (and COLLATION) throughout a database?
...
Do you really need to use "ALTER TABLE <table_name> MODIFY <column_name> ...". According to dev.mysql.com/doc/refman/5.5/en/alter-table.html it seems "ALTER TABLE <table_name> CONVERT TO CHARACTER SET ..." also chan...
std::function and std::bind: what are they, and when should they be used?
...nd to get g:
auto g = bind(f, _1, 4, _2);
This is more concise than actually writing a functor class to do it.
There are further examples in the article you link to. You generally use it when you need to pass a functor to some algorithm. You have a function or functor that almost does the job yo...
Is there a TRY CATCH command in Bash
... writing a shell script and need to check that a terminal app has been installed. I want to use a TRY/CATCH command to do this unless there is a neater way.
...
When would anyone use a union? Is it a remnant from the C-only days?
I have learned but don't really get unions. Every C or C++ text I go through introduces them (sometimes in passing), but they tend to give very few practical examples of why or where to use them. When would unions be useful in a modern (or even legacy) case? My only two guesses would be programming ...
What new capabilities do user-defined literals add to C++?
C++11 introduces user-defined literals which will allow the introduction of new literal syntax based on existing literals ( int , hex , string , float ) so that any type will be able to have a literal presentation.
...
How do you run your own code alongside Tkinter's event loop?
...tion for the after method:
def after(self, ms, func=None, *args):
"""Call function once after given time.
MS specifies the time in milliseconds. FUNC gives the
function which shall be called. Additional parameters
are given as parameters to the function call. Return
identifier...
How do I find where an exception was thrown in C++?
I have a program that throws an uncaught exception somewhere. All I get is a report of an exception being thrown, and no information as to where it was thrown. It seems illogical for a program compiled to contain debug symbols not to notify me of where in my code an exception was generated.
...