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How to 'bulk update' with Django?
...ings like incrementing rows:
from django.db.models import F
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
See the documentation.
However, note that:
This won't use ModelClass.save method (so if you have some logic inside it won't be triggered).
No django signals will be emitte...
What is the fastest way to check if a class has a function defined?
...tr() to get the attribute, and callable() to verify it is a method:
invert_op = getattr(self, "invert_op", None)
if callable(invert_op):
invert_op(self.path.parent_op)
Note that getattr() normally throws exception when the attribute doesn't exist. However, if you specify a default value (None...
surface plots in matplotlib
...esenting a set of points in 3D space. I want to plot a surface that covers all these points.
8 Answers
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Using pg_dump to only get insert statements from one table within database
I'm looking for a way to get all rows as INSERT statements from one specific table within a database using pg_dump in PostgreSQL.
...
关于php的socket初探 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...塞的古老模型：属于同步阻塞 IO 模型，代码如下：
socket_server.php
<?php
/**
* SocketServer Class
* By James.Huang <shagoo#gmail.com>
**/
set_time_limit(0);
class SocketServer
{
private static $socket;
function SocketServer($port)
{ ...
hidden symbol ... is referenced by DSO 剖析 - C/C++ - 清泛网 - 专注C/C++及内核技术
...因是符号(函数)未导出导致的，添加导出申明即可解决：__attribute__ ((visibility("default")) DSO 是动态共享对象，Linux报“hidden symbol ... is referenced by DSO”错误的原因是符号(函数)未导出导致的，添加导出申明即可解决：
__attribute__ (...
C++简练易用的线程池(threadpool)及上下文隔离的无锁线程池(isolated_threa...
...易用的线程池(threadpool)及上下文隔离的无锁线程池(isolated_threadpool)完整实现本文主要介绍两种C++线程池模型完整代码，经过实战考验的，效率已极致优化的代码，可直接用于实际项目开发。1、C++简练易用的线程池(threadpool)
完整...
How to get overall CPU usage (e.g. 57%) on Linux [closed]
...s was not tested nor used, it's an idea for people who do not want to install a utility or for something that works in any distribution. Some people think you can "apt-get install" anything.
NOTE: this is not the current CPU usage, but the overall CPU usage in all the cores since the system bootup...
What is SYSNAME data type in SQL Server?
...stored procedures etc within SQL Server.
For example, by executing Exec sp_help 'sys.tables' you will see that the column name is defined as sysname this is because the value of this is actually an object in itself (a table)
I would worry too much about it.
It's also worth noting that for those p...
How do I print the type or class of a variable in Swift?
...y<String>.self)")
Which outputs:
String(myvar0.dynamicType) -> __NSCFConstantString
String(myvar1.dynamicType) -> PureSwiftClass
String(myvar2.dynamicType) -> Int
String(myvar3.dynamicType) -> String
String(Int.self) -> Int
String((Int?).self -> Optional&...