大约有 40,000 项符合查询结果（耗时：0.0588秒） [XML]
Is there a way to instantiate objects from a string holding their class name?
...ce() { return new T; }
typedef std::map<std::string, Base*(*)()> map_type;
map_type map;
map["DerivedA"] = &createInstance<DerivedA>;
map["DerivedB"] = &createInstance<DerivedB>;
And then you can do
return map[some_string]();
Getting a new instance. Another idea is ...
How to convert a scala.List to a java.util.List?
...1,2,3))
From Scala 2.8 onwards:
import scala.collection.JavaConversions._
import scala.collection.mutable.ListBuffer
asList(ListBuffer(List(1,2,3): _*))
val x: java.util.List[Int] = ListBuffer(List(1,2,3): _*)
However, asList in that example is not necessary if the type expected is a Java List,...
Is there a way to access method arguments in Ruby?
...meters # => [[:req, :x], [:req, :y]]
You can use the special variable __method__ to get the name of the current method. So within a method the names of its parameters can be obtained via
args = method(__method__).parameters.map { |arg| arg[1].to_s }
You could then display the name and value ...
how to unit test file upload in django
In my django app, I have a view which accomplishes file upload.The core snippet is like this
10 Answers
...
How can I profile Python code line-by-line?
...
I believe that's what Robert Kern's line_profiler is intended for. From the link:
File: pystone.py
Function: Proc2 at line 149
Total time: 0.606656 s
Line # Hits Time Per Hit % Time Line Contents
=================================================...
How do I find the location of my Python site-packages directory?
...ysconfig module instead:
python3 -c 'import sysconfig; print(sysconfig.get_paths()["purelib"])'
The per user site-packages directory (PEP 370) is where Python installs your local packages:
python -m site --user-site
If this points to a non-existing directory check the exit status of Python and ...
Running unittest with typical test directory structure
...e TestLoader class).
For example for a directory structure like this:
new_project
├── antigravity.py
└── test_antigravity.py
You can just run:
$ cd new_project
$ python -m unittest test_antigravity
For a directory structure like yours:
new_project
├── antigravity
│ ...
Speed comparison with Project Euler: C vs Python vs Erlang vs Haskell
...
Using GHC 7.0.3, gcc 4.4.6, Linux 2.6.29 on an x86_64 Core2 Duo (2.5GHz) machine, compiling using ghc -O2 -fllvm -fforce-recomp for Haskell and gcc -O3 -lm for C.
Your C routine runs in 8.4 seconds (faster than your run probably because of -O3)
The Haskell solution runs in...
How to measure time taken between lines of code in python?
...
If you want to measure CPU time, can use time.process_time() for Python 3.3 and above:
import time
start = time.process_time()
# your code here
print(time.process_time() - start)
First call turns the timer on, and second call tells you how many seconds have elapsed.
The...
iOS change navigation bar title font and color
...is works with no problem when only one NavBar is in the view
hierarchy. It appears that secondary NavBars in the same stack are ignored. (Note that if you show the master navigation controller's navBar all the other custom navBar settings are ignored).
Gotchas (deux)
Some of these are repeated wh...