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Referring to the null object in Python
...t;> NoneType = type(None)
>>> id(None)
10748000
>>> my_none = NoneType()
>>> id(my_none)
10748000
>>> another_none = NoneType()
>>> id(another_none)
10748000
>>> def function_that_does_nothing(): pass
>>> return_value = function_that_...
How to declare a variable in MySQL?
... For example, SELECT DISTINCT IFNULL(@var:=Name,'unknown') FROM Customers ORDER BY <some non-indexed expression> LIMIT 10 appears to evaluate the variable assignments before the order-by is done, so that the returned value of @var might not even relate to any of the returned rows. The docs d...
How to do a less than or equal to filter in Django queryset?
...
Less than or equal:
User.objects.filter(userprofile__level__lte=0)
Greater than or equal:
User.objects.filter(userprofile__level__gte=0)
Likewise, lt for less than and gt for greater than. You can find them all in the documentation.
...
Using Django time/date widgets in custom form
... the proper field names from your model):
from django import forms
from my_app.models import Product
from django.contrib.admin import widgets
class ProductForm(forms.ModelForm):
class Meta:
model = Product
def __init__(self, *args, **kwargs):
...
How to convert a scala.List to a java.util.List?
...1,2,3))
From Scala 2.8 onwards:
import scala.collection.JavaConversions._
import scala.collection.mutable.ListBuffer
asList(ListBuffer(List(1,2,3): _*))
val x: java.util.List[Int] = ListBuffer(List(1,2,3): _*)
However, asList in that example is not necessary if the type expected is a Java List,...
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 ...
How can I uninstall an application using PowerShell?
...
$app = Get-WmiObject -Class Win32_Product | Where-Object {
$_.Name -match "Software Name"
}
$app.Uninstall()
Edit: Rob found another way to do it with the Filter parameter:
$app = Get-WmiObject -Class Win32_Product `
-Filter "N...
After Installing Java JDK 7 For Mac OS X - mvn -version still shows java version 1.6.0_31
...ly found the answer here:
http://www.adam-bien.com/roller/abien/entry/java_se_development_kit_7
You should use JAVA_HOME=$(/usr/libexec/java_home) instead on a Mac and then set the current jdk via "Java Preferences.app".
Set JAVA_HOME in ~/.profile
...
Where in a virtualenv does the custom code go?
...our packages right inside:
/foobar
/bin
{activate, activate.py, easy_install, python}
/include
{python2.6/...}
/lib
{python2.6/...}
/mypackage1
__init__.py
/mypackage2
__init__.py
The advantage of this approach is that you can always be sure to find find the activate...
Remove all occurrences of a value from a list?
...ython 3.x
>>> x = [1,2,3,2,2,2,3,4]
>>> list(filter((2).__ne__, x))
[1, 3, 3, 4]
or
>>> x = [1,2,3,2,2,2,3,4]
>>> list(filter(lambda a: a != 2, x))
[1, 3, 3, 4]
Python 2.x
>>> x = [1,2,3,2,2,2,3,4]
>>> filter(lambda a: a != 2, x)
[1, 3, 3...