大约有 47,000 项符合查询结果（耗时：0.0371秒） [XML]
Create a “with” block on several context managers? [duplicate]
...rite:
with A() as X, B() as Y, C() as Z:
do_something()
This is normally the best method to use, but if you have an unknown-length list of context managers you'll need one of the below methods.
In Python 3.3, you can enter an unknown-length list of context managers by using contextlib.Exit...
What is the proper way to re-attach detached objects in Hibernate?
...e to the DB,
and overwrite any intervening updates.
refresh() cannot be called on a detached entity.
lock() cannot be called on a detached entity,
and even if it could, and it did reattach the entity,
calling 'lock' with argument 'LockMode.NONE'
implying that you are locking, but not locking,
i...
Difference between shared objects (.so), static libraries (.a), and DLL's (.so)?
... and shared objects are just different terms for the same thing - Windows calls them DLLs, while on UNIX systems they're shared objects, with the general term - dynamically linked library - covering both (even the function to open a .so on UNIX is called dlopen() after 'dynamic library').
They are ...
Printf width specifier to maintain precision of floating-point value
...ier which can be applied to a floating point specifier that would automatically format the output to the necessary number of significant digits such that when scanning the string back in, the original floating point value is acquired?
...
Are list-comprehensions and functional functions faster than “for loops”?
...ike map() , filter() and reduce() faster than a for loop? Why, technically, they run in a C speed , while the for loop runs in the python virtual machine speed ?.
...
Passing parameters to JavaScript files
...it or define a new object. The intent is to create a global namespace, normally I will use sub namespaces so this line helps to avoid re-defining the top level namespace. 2) Yes, it has created a singleton.
– Naeem Sarfraz
Apr 7 '15 at 9:41
...
After Installing Java JDK 7 For Mac OS X - mvn -version still shows java version 1.6.0_31
Oracle released Java JDK 7 on April 26 for Mac OS X. I followed the install instructions and when I do java -version in a terminal window I get:
...
How do I catch a numpy warning like it's an exception (not just for testing)?
...ng: divide by zero encountered in divide
array([0])
>>> np.seterr(all='print')
{'over': 'warn', 'divide': 'warn', 'invalid': 'warn', 'under': 'ignore'}
>>> np.array([1])/0 #'print' mode
Warning: divide by zero encountered in divide
array([0])
This means that the warning you see...
What are some uses of template template parameters?
...alue) {
}
Here, H is a template, but I wanted this function to deal with all specializations of H.
NOTE: I've been programming c++ for many years and have only needed this once. I find that it is a rarely needed feature (of course handy when you need it!).
I've been trying to think of good examp...
What is a plain English explanation of “Big O” notation?
...a notation "Θ" (which is a two-side bound). In my experience, this is actually typical of discussions in non-academic settings. Apologies for any confusion caused.
Big O complexity can be visualized with this graph:
The simplest definition I can give for Big-O notation is this:
Big-O notation is ...