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Python regular expressions return true/false
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– Ignacio Vazquez-Abrams
Jul 5 '11 at 0:05
Thanks -- corrected that. I was just going by what I saw in the REPL.
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How to append text to a text file in C++?
...makes sure that file gets created if it doesn't exist and also adds bit of error checks.
static void appendLineToFile(string filepath, string line)
{
std::ofstream file;
//can't enable exception now because of gcc bug that raises ios_base::failure with useless message
//file.exceptions(...
Compare object instances for equality by their attributes
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You should implement the method __eq__:
class MyClass:
def __init__(self, foo, bar):
self.foo = foo
self.bar = bar
def __eq__(self, other):
if not isinstance(other, MyClass):
# don't attempt to compare against ...
Difference between \b and \B in regex
...ition. no?.
– Kosem
Jun 17 '19 at 8:05
add a comment
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Is there a Python caching library?
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From Python 3.2 you can use the decorator @lru_cache from the functools library.
It's a Last Recently Used cache, so there is no expiration time for the items in it, but as a fast hack it's very useful.
from functools import lru_cache
@lru_cache(maxsize=256)
def f(x):
...
Inverse dictionary lookup in Python
...s slow as yours, because it creates a list from the dict twice.
key = dict_obj.keys()[dict_obj.values().index(value)]
Or if you prefer brevity over readability you can save one more character with
key = list(dict_obj)[dict_obj.values().index(value)]
And if you prefer efficiency, @PaulMcGuire's...
How to invoke the super constructor in Python?
...on-3.x the process has been simplified:
Python-2.x
class A(object):
def __init__(self):
print "world"
class B(A):
def __init__(self):
print "hello"
super(B, self).__init__()
Python-3.x
class A(object):
def __init__(self):
print("world")
class B(A):
def __init__(self):
print...
C/C++ line number
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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...
How does __proto__ differ from constructor.prototype?
...bject layout
The most surprising thing for me was discovering that Object.__proto__ points to Function.prototype, instead of Object.prototype, but I'm sure there's a good reason for that :-)
I paste the code mentioned in the image here as well for if anyone wants to test it. Note that some propert...
计算统计特征（正态分布）函数及实例 - C/C++ - 清泛网 - 专注C/C++及内核技术
...实例main函数：#include "stdafx.h"#include "stdev.h"#include <map>int _tmain(int argc, _TCHAR* argv[]){std::map<int, int> map_...main函数：
#include "stdafx.h"
#include "stdev.h"
#include <map>
int _tmain(int argc, _TCHAR* argv[])
{
std::map<int, int> map_test;
map_test[0] = 100;...