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Why does Python use 'magic methods'?
...s', e.g. to make its length available, an object implements a method, def __len__(self) , and then it is called when you write len(obj) .
...
Django - filtering on foreign key properties
...
Asset.objects.filter( project__name__contains="Foo" )
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adito-gateway -华为云免费SSL VPN解决方案 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...tar.gz
解压出来后，移动到usr目录
[root@adito mnt]# mv jdk1.7.0_17 /usr
配置java 参数
alternatives --install /usr/bin/java java /usr/jdk1.7.0_17/jre/bin/java 20000
alternatives --install /usr/bin/javaws javaws /usr/jdk1.7.0_17/jre/bin/javaws 20000
alternatives --install /usr/...
Any gotchas using unicode_literals in Python 2.6?
...ng: utf-8
name = 'helló wörld from two'
one.py
# encoding: utf-8
from __future__ import unicode_literals
import two
name = 'helló wörld from one'
print name + two.name
The output of running python one.py is:
Traceback (most recent call last):
File "one.py", line 5, in <module>
...
List changes unexpectedly after assignment. How do I clone or copy it to prevent this?
While using new_list = my_list , any modifications to new_list changes my_list everytime. Why is this, and how can I clone or copy the list to prevent it?
...
Calculate difference in keys contained in two Python dictionaries
...nged values
(4) keys same in both and unchanged values
"""
def __init__(self, current_dict, past_dict):
self.current_dict, self.past_dict = current_dict, past_dict
self.set_current, self.set_past = set(current_dict.keys()), set(past_dict.keys())
self.intersect = s...
Efficient way to apply multiple filters to pandas DataFrame or Series
...turn op(x[col],n)
In [15]: def f(x, *b):
return x[(np.logical_and(*b))]
In [16]: b1 = b(df, 'col1', ge, 1)
In [17]: b2 = b(df, 'col1', le, 1)
In [18]: f(df, b1, b2)
Out[18]:
col1 col2
1 1 11
Update: pandas 0.13 has a query method for these kind of use cases, assuming c...
Understanding repr( ) function in Python
...x and then calls repr('foo').
>>> repr(x)
"'foo'"
>>> x.__repr__()
"'foo'"
repr actually calls a magic method __repr__ of x, which gives the string containing the representation of the value 'foo' assigned to x. So it returns 'foo' inside the string "" resulting in "'foo'". The ...
Resolve build errors due to circular dependency amongst classes
...riting a compiler. And you see code like this.
// file: A.h
class A {
B _b;
};
// file: B.h
class B {
A _a;
};
// file main.cc
#include "A.h"
#include "B.h"
int main(...) {
A a;
}
When you are compiling the .cc file (remember that the .cc and not the .h is the unit of compilation), you ne...
What is the purpose of willSet and didSet in Swift?
...ws conditional setting of an actual stored property
//True model data
var _test : Int = 0
var test : Int {
get {
return _test
}
set (aNewValue) {
//I've contrived some condition on which this property can be set
if (aNewValue != test) {
_test = aNewV...