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'const string' vs. 'static readonly string' in C#
...is why it can't be used as the default parameter for a method (compilation error) for example. The value stored in it can be obfuscated.
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How to convert list of tuples to multiple lists?
...
xs, ys = [x for x, y in zs], [y for x, y in zs]
return xs, ys
if __name__ == '__main__':
from timeit import timeit
setup_string='''\
N = 2000000
xs = list(range(1, N))
ys = list(range(N+1, N*2))
zs = list(zip(xs, ys))
from __main__ import t1, t2, t3
'''
print(f'zip:\t\t{timeit(...
Use numpy array in shared memory for multiprocessing
...not available anymore) and @Henry Gomersall's answers. You could use shared_arr.get_lock() to synchronize access when needed:
shared_arr = mp.Array(ctypes.c_double, N)
# ...
def f(i): # could be anything numpy accepts as an index such another numpy array
with shared_arr.get_lock(): # synchroniz...
What is content-type and datatype in an AJAX request?
...on/json",
data : dataAttribute,
success : function() {
},
error : function(error) {
}
});
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decorators in the python standard lib (@deprecated specifically)
...ed
when the function is used."""
@functools.wraps(func)
def new_func(*args, **kwargs):
warnings.simplefilter('always', DeprecationWarning) # turn off filter
warnings.warn("Call to deprecated function {}.".format(func.__name__),
category=DeprecationW...
The tilde operator in Python
...s operator.invert. To support this operator in your own class, give it an __invert__(self) method.
>>> import operator
>>> class Foo:
... def __invert__(self):
... print 'invert'
...
>>> x = Foo()
>>> operator.invert(x)
invert
>>> ~x
invert
Any ...
How to base64 encode image in linux bash / shell
...
You need to use cat to get the contents of the file named 'DSC_0251.JPG', rather than the filename itself.
test="$(cat DSC_0251.JPG | base64)"
However, base64 can read from the file itself:
test=$( base64 DSC_0251.JPG )
...
if A vs if A is not None:
...
The statement
if A:
will call A.__nonzero__() (see Special method names documentation) and use the return value of that function. Here's the summary:
object.__nonzero__(self)
Called to implement truth value testing and the built-in operation bool()...
BugTrap：程序崩溃快照、bug跟踪之利器 - C/C++ - 清泛网 - 专注C/C++及内核技术
...法：
BOOL CMarketInfoApp::InitInstance()
{
...
SetRegistryKey(_T("应用程序向导生成的本地应用程序"));
// 开启程序崩溃感知
SetUnhandledExceptionFilter(MyUnhandledExceptionFilter);
...
}
逻辑处理MyBugTrap.cpp：
#include "stdafx.h"
#include "Bug...
MongoDB仿关系型数据库Group聚合例子 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...数据
Dictionary dic = new Dictionary();
dic["_userName"] = ""; // 与原字段名区分开
dic["_date"] = "";
dic["_data"] = "0";
MongoServer server = new MongoClient(MongoConnStr).GetServer();
MongoDatabase db = serve...