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Count number of records returned by group by
...rGroup,
COUNT(*) OVER () AS TotalRecords
from temptable
group by column_1, column_2, column_3, column_4
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How to overload __init__ method based on argument type?
...to use classmethods. For instance:
>>> class MyData:
... def __init__(self, data):
... "Initialize MyData from a sequence"
... self.data = data
...
... @classmethod
... def fromfilename(cls, filename):
... "Initialize MyData from a file"
... ...
TypeError: method() takes 1 positional argument but 2 were given
...
In Python, this:
my_object.method("foo")
...is syntactic sugar, which the interpreter translates behind the scenes into:
MyClass.method(my_object, "foo")
...which, as you can see, does indeed have two arguments - it's just that the first o...
How to determine a Python variable's type?
...
It is so simple. You do it like this.
print(type(variable_name))
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Relative paths in Python
..., you want to do something like this:
import os
dirname = os.path.dirname(__file__)
filename = os.path.join(dirname, 'relative/path/to/file/you/want')
This will give you the absolute path to the file you're looking for. Note that if you're using setuptools, you should probably use its package re...
C/C++ line number
...
You should use the preprocessor macro __LINE__ and __FILE__. They are predefined macros and part of the C/C++ standard. During preprocessing, they are replaced respectively by a constant string holding an integer representing the current line number and by the cu...
When are C++ macros beneficial? [closed]
...
As wrappers for debug functions, to automatically pass things like __FILE__, __LINE__, etc:
#ifdef ( DEBUG )
#define M_DebugLog( msg ) std::cout << __FILE__ << ":" << __LINE__ << ": " << msg
#else
#define M_DebugLog( msg )
#endif
...
TLSF源码及算法介绍 - 开源 & Github - 清泛网 - 专注C/C++及内核技术
...s of the GNU Lesser General Public License Version 2.1
*
*/
#ifndef _TLSF_H_
#define _TLSF_H_
#include <sys/types.h>
extern size_t init_memory_pool(size_t, void *);
extern size_t get_used_size(void *);
extern size_t get_max_size(void *);
extern void destroy_memory_pool(void *);
ext...
What do all of Scala's symbolic operators mean?
... // Syntactic sugar/composition or common method
<= // Common method
_._ // Typo, though it's probably based on Keyword/composition
:: // Common method
:+= // Common method
The exact meaning of most of these methods depend on the class that is defining them. For example, <= on Int ...
C Macro definition to determine big endian or little endian machine?
...byte orders, ready to be put into a file called order32.h:
#ifndef ORDER32_H
#define ORDER32_H
#include <limits.h>
#include <stdint.h>
#if CHAR_BIT != 8
#error "unsupported char size"
#endif
enum
{
O32_LITTLE_ENDIAN = 0x03020100ul,
O32_BIG_ENDIAN = 0x00010203ul,
O32_PDP_E...