大约有 40,000 项符合查询结果（耗时：0.0516秒） [XML]
Inverse dictionary lookup in Python
...o guarantee that it returns a single value and it does not need to be lexically first only that it be the first match and that it's behavior is stable (multiple calls on same dict over time should yield same matching element). Unless dictionaries rearrange their unmodified hashes over time as other...
How to convert timestamp to datetime in MySQL?
...)) ; to compare dates, I replace 2019-05*02 a formatted datetime object in php. Thnaks.
– Mantisse
Apr 12 '19 at 18:00
1
...
ES6 class variable alternatives
...is syntax working.
The notes in the ES wiki for the proposal in ES6 (maximally minimal classes) note:
There is (intentionally) no direct declarative way to define either prototype data properties (other than methods) class properties, or instance property
Class properties and prototype data proper...
Chaining multiple filter() in Django, is this a bug?
I always assumed that chaining multiple filter() calls in Django was always the same as collecting them in a single call.
4...
unable to copy/paste in mingw shell
...ms to be a bit buggy. For instance running an an executable via cli (e.g. php -version results in empty output and forces me to restart the shell). Waiting for a new update, hopefully which will fix this.
share
|
...
Why prefer two's complement over sign-and-magnitude for signed numbers?
...o add them.
Two's complement addition is very simple. You add numbers normally and any carry bit at the end is discarded. So they're added as follows:
0010
+ 1111
=10001
= 0001 (discard the carry)
0001 is 1, which is the expected result of "2+(-1)".
But in your "intuitive" method, adding is m...
MySQL DROP all tables, ignoring foreign keys
Is there a nice easy way to drop all tables from a MySQL database, ignoring any foreign key constraints that may be in there?
...
What are sessions? How do they work?
...
@user137717 yes that is a possibility if you allow access to the session to literally "every one that presents the correct session id". There are a number of restrictions you can put in place, one of the easiest and most common is to store the client IP in the session: ...
Logical operators for boolean indexing in Pandas
...Error: The truth value of an array is ambiguous. Use a.empty, a.any() or a.all().
when used as a boolean value. That's because its unclear when it should be True or False. Some users might assume they are True if they have non-zero length, like a Python list. Others might desire for it to be True ...
Understanding __get__ and __set__ and Python descriptors
...th the Temperature class). For example:
temp=Temperature()
temp.celsius #calls celsius.__get__
Accessing the property you assigned the descriptor to (celsius in the above example) calls the appropriate descriptor method.
instance in __get__ is the instance of the class (so above, __get__ would r...