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Getting the name of a child class in the parent class (static context)
...ot possible. in php4 you could implement a terrible hack (examine the debug_backtrace()) but that method does not work in PHP5. references:
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edit: an example of late static binding in PHP 5.3 (mentioned in comments). note there are potential problems in it's current implementat...
How to select rows from a DataFrame based on column values?
...have multiple values you want to include, put them in a
list (or more generally, any iterable) and use isin:
print(df.loc[df['B'].isin(['one','three'])])
yields
A B C D
0 foo one 0 0
1 bar one 1 2
3 bar three 3 6
6 foo one 6 12
7 foo three 7 14
Note,...
Python function global variables?
...hem, is the following a valid way to go about using them? (I am trying to call the global copy of a variable created in a separate function.)
...
How do you create nested dict in Python?
...he following:
d = {} # can use defaultdict(dict) instead
for row in file_map:
# derive row key from something
# when using defaultdict, we can skip the next step creating a dictionary on row_key
d[row_key] = {}
for idx, col in enumerate(row):
d[row_key][idx] = col
Ac...
How to extract the year from a Python datetime object?
...ew times and you'll be prompted with the members of the "now" object:
now.__add__ now.__gt__ now.__radd__ now.__sub__ now.fromordinal now.microsecond now.second now.toordinal now.weekday
now.__class__ now.__hash__ ...
C++中判断文件、目录是否存在的几种方法 - C/C++ - 清泛网 - 专注C/C++及内核技术
...
if(fh == NULL)
{
printf("%s","can not open the file");
}
三、_access
当然C中还有一种方式是直接调用c的函数库。
就是函数 int _access(const char* path,int mode);
这个函数的功能十分强大。
可以看看msdn的详细介绍
#include <io.h>
#include ...
Efficient evaluation of a function at every cell of a NumPy array
...t be faster than the "manual" double loop iteration and assignment through all the array elements. Especially, because it stores the result to a newly created variable (and not directly to the initial input). Thanks a lot for your reply though:)
– Peter
Oct 9 '...
Clean code to printf size_t in C++ (or: Nearest equivalent of C99's %z in C++)
...isual C++ for instance use %Iu and %Id respectively, I think that gcc will allow you to use %zu and %zd.
You could create a macro:
#if defined(_MSC_VER) || defined(__MINGW32__) //__MINGW32__ should goes before __GNUC__
#define JL_SIZE_T_SPECIFIER "%Iu"
#define JL_SSIZE_T_SPECIFIER "%Id"
...
C99 stdint.h header and MS Visual Studio
... Without this header I have no definitions for useful types such as uint32_t, etc.
7 Answers
...
Rails: around_* callbacks
...classes/ActiveRecord/Callbacks.html , but don't understand when the around_* callbacks are triggered in relation to before_* and after_* .
...