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Multiple columns index when using the declarative ORM extension of sqlalchemy
...e just Column objects, index=True flag works normally:
class A(Base):
__tablename__ = 'table_A'
id = Column(Integer, primary_key=True)
a = Column(String(32), index=True)
b = Column(String(32), index=True)
if you'd like a composite index, again Table is present here as usual you ju...
How does python numpy.where() work?
... sort of logical operation on a numpy array returns a boolean array. (i.e. __gt__, __lt__, etc all return boolean arrays where the given condition is true).
E.g.
x = np.arange(9).reshape(3,3)
print x > 5
yields:
array([[False, False, False],
[False, False, False],
[ True, Tru...
How to disable GCC warnings for a few lines of code
...
TL;DR: If it works, avoid, or use specifiers like __attribute__, otherwise _Pragma.
This is a short version of my blog article
Suppressing Warnings in GCC and Clang.
Consider the following Makefile
CPPFLAGS:=-std=c11 -W -Wall -pedantic -Werror
.PHONY: all
all: puts
fo...
Try catch statements in C
...ou can simulate them to a degree with setjmp and longjmp calls.
static jmp_buf s_jumpBuffer;
void Example() {
if (setjmp(s_jumpBuffer)) {
// The longjmp was executed and returned control here
printf("Exception happened here\n");
} else {
// Normal code execution starts here
Te...
Formatting numbers (decimal places, thousands separators, etc) with CSS
....
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toLocaleString
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How to check version of python modules?
...
I suggest using pip in place of easy_install. With pip, you can list all installed packages and their versions with
pip freeze
In most linux systems, you can pipe this to grep(or findstr on Windows) to find the row for the particular package you're interest...
How can I recover the return value of a function passed to multiprocessing.Process?
... For example like this:
import multiprocessing
def worker(procnum, return_dict):
'''worker function'''
print str(procnum) + ' represent!'
return_dict[procnum] = procnum
if __name__ == '__main__':
manager = multiprocessing.Manager()
return_dict = manager.dict()
jobs = []
...
Should I implement __ne__ in terms of __eq__ in Python?
I have a class where I want to override the __eq__ method. It seems to make sense that I should override the __ne__ method as well, but does it make sense to implement __ne__ in terms of __eq__ as such?
...
error LNK2019: 无法解析的外部符号_socket，该符号在函数 中被引用 - C/C+...
error LNK2019: 无法解析的外部符号_socket，该符号在函数 中被引用1>NetClient.obj : error LNK2019: 无法解析的外部符号 _closesocket@4，该符号在函数 _main 中被引用1>NetClient.obj : error L...1>NetClient.obj : error LNK2019: 无法解析的外部符号 _closesocket@...
Short description of the scoping rules?
...ithout explicit declaration, but writing to it without declaring global(var_name) will instead create a new local instance.
– Peter Gibson
Jun 27 '12 at 5:53
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