大约有 40,000 项符合查询结果（耗时：0.0380秒） [XML]
Zero-based month numbering [closed]
...
The use of zero to start counting is actually an optimization trick from Assembly programmers. Instead of assigning 1 to the count register, they XOR'ed the register with itself, which was slightly faster in CPU cycles. This meant that counting would start with 0 an...
Select distinct values from a table field
...ant any ordering to be applied to a query, not even the default ordering, call order_by() with no parameters.
and distinct() in the note where it discusses issues with using distinct() with ordering.
To query your DB, you just have to call:
models.Shop.objects.order_by().values('city').distinct(...
If a DOM Element is removed, are its listeners also removed from memory?
...veChild() for example).
However, this isn't true; the jQuery library actually has an internal method (which is undocumented and in theory could be changed at any time) called cleanData() (here is what this method looks like) which automatically cleans up all the data/events associated with an elem...
Pythonic way to combine FOR loop and IF statement
...this case). But it can also be called directly, it is a part of the public API. Private names are specifically defined as having at most one trailing underscore, to provide exception for special method names - and they are subject to name mangling when lexically in class scopes. See docs.python.org/...
The case against checked exceptions
...jlsberg and his work, this argument has always struck me as bogus. It basically boils down to:
"Checked exceptions are bad because programmers just abuse them by always catching them and dismissing them which leads to problems being hidden and ignored that would otherwise be presented to the us...
What is Java String interning?
...p://docs.oracle.com/javase/7/docs/api/java/lang/String.html#intern()
Basically doing String.intern() on a series of strings will ensure that all strings having same contents share same memory. So if you have list of names where 'john' appears 1000 times, by interning you ensure only one 'john' is a...
Post data to JsonP
Is it possible to post data to JsonP? Or does all data have to be passed in the querystring as a GET request?
7 Answers
...
How do I convert an existing callback API to promises?
I want to work with promises but I have a callback API in a format like:
20 Answers
20...
Why use Abstract Base Classes in Python?
...emented classes.
Long version
There is a contract between a class and its callers. The class promises to do certain things and have certain properties.
There are different levels to the contract.
At a very low level, the contract might include the name of a method or its number of parameters.
In a s...
Python: What OS am I running on?
... The release lookup for python on Windows appears to use the Win32 api function GetVersionEx at its core. The notes at the top of this Microsoft article about that function could be relevant: msdn.microsoft.com/en-us/library/windows/desktop/…
– theferrit32
...