[global statement] 在线程里,默认所有变量都是本线程局部变量,要想访问全局变量,则要先用global声明. 如全局有变量totalCount,线程中有语句 totalCount += 1,运行时会报错,totalCount未赋值.此时在赋值语句前加上global totalCount声明即可.…

1 Global The global statement and its nonlocal cousin are the only things that are remotely like declaration statements in Python. They are not type or size declarations; they are namespace declarations. The global statement tells Python that a funct…

每个函数都有着自已的命名空间,叫做局部名字空间,它记录了函数的变量,包括函数的参数和局部定义的变量.每个模块拥有它自已的命名空间,叫做全局命名空间,它记录了模块的变量,包括函数.类.其它导入的模块.模块级的变量和常量.还有就是内置命名空间,任何模块均可访问它,它存放着内置的函数和异常. 按照如下顺序: 1.局部命名空间 - 特指当前函数或类的方法.如果函数定义了一个局部变量,Python将使用这个变量,然后停止搜索. 2.全局命名空间 - 特指当前的模块.如果模块定义了一个变量,函数或类,Pyt…

Before introducing classes, I first have to tell you something about Python's scope rules. Class definitions play some neat tricks with namespaces, and you need to know how scopes and namespaces work to fully understand what's going on. Incidentally,…

From:http://learnpythonthehardway.org/book/ex37.html 1. with X as Y: pass 1.1 yield 2. exec 2.1 namespace 3. lambda 3.1 map 3.2 map and reduce 4. raise KEYWORD DESCRIPTION EXAMPLE and Logical and. True and False == False as (1) Part of the with-as st…

Dictionaries A dictionary is like a list, but more general. In a list, the indices have to be integers; in a dictionary they can be (almost) any type.You can think of a dictionary as a mapping between a set of indices (which are called keys) and a se…

An optimization for InnoDB tables that can speed up lookups using = and IN operators, by constructing a hash index in memory. MySQL monitors index searches for InnoDB tables, and if queries could benefit from a hash index, it builds one automatically…

## 9. Classes 类 Compared with other programming languages, Python's class mechanism adds classes with a minimum of new syntax and semantics. It is a mixture of the class mechanisms found in C++ and Modula-3. Python classes provide all the standard fe…

The code for this tutorial can be downloaded here: threadworms.py or from GitHub. This code works with Python 3 or Python 2, and you need Pygame installed as well in order to run it. Click the animated gif to view a larger version. This is a tutorial…

global log 127.0.0.1 local3 maxconn 65535 chroot /usr/local/haproxy uid 500 gid 500 daemon ssl-default-bind-options no-sslv3 force-sslv3 This option enforces use of SSLv3 only on SSL connections instantiated from this listener. SSLv3 is generally les…