python---pyc pyo文件详解

http://blog.csdn.net/balabalamerobert/article/details/2683029#comments

 http://blog.csdn.net/zhengsenlie/article/details/30511257

http://www.cnblogs.com/txw1958/archive/2012/02/23/pyc_introduce.html

http://blog.csdn.net/I2Cbus/article/details/41383401

http://www.jianshu.com/p/03d81eb9ac9b

http://download.csdn.net/download/demonlifewnb/9408511

http://blog.csdn.net/chenggong2dm/article/category/768210

http://nedbatchelder.com/blog/200804/the_structure_of_pyc_files.html

http://www.cppblog.com/lauer3912/archive/2011/08/12/153233.aspx

https://docs.python.org/release/2.7/library/dis.html#python-bytecode-instructions

https://docs.python.org/release/2.7/library/

http://www.cnblogs.com/kym/archive/2012/05/14/2498728.html

把一个py文件编译为pyc文件了。(假设在windows环境下)
import py_compile
py_compile.compile(r'H:game est.py')
py_compile.compile('webmail_sina.py') # Linux环境

批量生成pyc文件 
>>> import compileall
>>> compileall.compile_dir(r'/home/codemo/Desktop/python')

python -O -m py_compile test.py   生成 test.pyo  

python  -m py_compile test.py      生成test.pyc

    pyc文件，是Python编译后的字节码（bytecode）文件。只要你运行了py文件，python编译器就会自动生成一个对应的pyc字节码文件。

这个pyc字节码文件，经过python解释器，会生成机器码运行（这也是为什么pyc文件可以跨平台部署，类似于Java的跨平台，java中JVM运行的字节码文件）

。下次调用直接调用pyc，而不调用py文件。直到你这个py文件有改变。python解释器会检查pyc文件中的生成时间，对比py文件的修改时间，如果py更新，那么就生成新的pyc。

    pyo文件，是python编译优化后的字节码文件。pyo文件在大小上，一般小于等于pyc文件。

python文档是这样描述的：这个优化没有多大作用，只是移除了断言。

原文如下：

 When the Python interpreter is invoked with the -O flag, optimized code is generated and stored in .pyo files.

The optimizer currently doesn’t help much; it only removes assert statements.

When -O is used, all bytecode is optimized;

.pyc files are ignored and .py files are compiled to optimized bytecode.

    

    至于速度，运行几乎一样，加载pyc和pyo稍占优势。python文档是这样说的：   

    A program doesn’t run any faster when it is read from a .pyc or .pyo file than when it is read from a .py file;

the only thing that’s faster about .pyc or .pyo files is the speed with which they are loaded.