python编译py成pyc和pyo

pyc是一种二进制文件，是由py文件经过编译后，生成的文件，是一种byte code，py文件变成pyc文件后，加载的速度有所提高，而且pyc是一种跨平台的字节码，是由python的虚拟机来执行的，这个是类似于JAVA或 者.NET的虚拟机的概念。pyc的内容，是跟python的版本相关的，不同版本编译后的pyc文件是不同的，2.5编译的pyc文件，2.4版本的 python是无法执行的。

1.编译单个py文件

(1)

直接在命令行下执行 python -m py_compile file.py

(2)

在python代码中使用py_compile.compile函数来编译。该函数的帮助信息如下：

 

Help on function compile in module py_compile:

compile(file, cfile=None, dfile=None, doraise=False)
    Byte-compile one Python source file to Python bytecode.
    
    Arguments:
    
    file:    source filename
    cfile:   target filename; defaults to source with 'c' or 'o' appended
             ('c' normally, 'o' in optimizing mode, giving .pyc or .pyo)
    dfile:   purported filename; defaults to source (this is the filename
             that will show up in error messages)
    doraise: flag indicating whether or not an exception should be
             raised when a compile error is found. If an exception
             occurs and this flag is set to False, a string
             indicating the nature of the exception will be printed,
             and the function will return to the caller. If an
             exception occurs and this flag is set to True, a
             PyCompileError exception will be raised.
    
    Note that it isn't necessary to byte-compile Python modules for
    execution efficiency -- Python itself byte-compiles a module when
    it is loaded, and if it can, writes out the bytecode to the
    corresponding .pyc (or .pyo) file.
    
    However, if a Python installation is shared between users, it is a
    good idea to byte-compile all modules upon installation, since
    other users may not be able to write in the source directories,
    and thus they won't be able to write the .pyc/.pyo file, and then
    they would be byte-compiling every module each time it is loaded.
    This can slow down program start-up considerably.
    
    See compileall.py for a script/module that uses this module to
    byte-compile all installed files (or all files in selected
    directories).

 

 

[baichuan@zjdw-odmz-0009 python]$ ls
adp_group_info_data  adp_group_info.py  db_api.py  db_api.pyc  dump_rmc_area_ip.py  dump_rmc_tag.py
[baichuan@zjdw-odmz-0009 python]$ python
Python 2.6.6 (r266:84292, Jan 22 2014, 09:42:36) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import py_compile
>>> py_compile.compile("adp_group_info.py")
>>> py_compile.compile("/home/baichuan/yxc/python/dump_rmc_tag.py")
>>> quit()
[baichuan@zjdw-odmz-0009 python]$ ls
adp_group_info_data  adp_group_info.py  adp_group_info.pyc  db_api.py  db_api.pyc  dump_rmc_area_ip.py  dump_rmc_tag.py  dump_rmc_tag.pyc
[baichuan@zjdw-odmz-0009 python]$ 

 

2.批量生成pyc文件

在python代码中使用compileall.compile_dir函数来编译。该函数的帮助信息如下：

Help on function compile_dir in module compileall:

compile_dir(dir, maxlevels=10, ddir=None, force=0, rx=None, quiet=0)
    Byte-compile all modules in the given directory tree.
    
    Arguments (only dir is required):
    
    dir:       the directory to byte-compile
    maxlevels: maximum recursion level (default 10)
    ddir:      if given, purported directory name (this is the
               directory name that will show up in error messages)
    force:     if 1, force compilation, even if timestamps are up-to-date
    quiet:     if 1, be quiet during compilation

[baichuan@zjdw-odmz-0009 python]$ ls
adp_group_info_data  adp_group_info.py  db_api.py  dump_rmc_area_ip.py  dump_rmc_tag.py
[baichuan@zjdw-odmz-0009 python]$ python
Python 2.6.6 (r266:84292, Jan 22 2014, 09:42:36) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import compileall
>>> compileall.compile_dir("/home/baichuan/yxc/python/")
Listing /home/baichuan/yxc/python/ ...
Compiling /home/baichuan/yxc/python/adp_group_info.py ...
Compiling /home/baichuan/yxc/python/db_api.py ...
Compiling /home/baichuan/yxc/python/dump_rmc_area_ip.py ...
Compiling /home/baichuan/yxc/python/dump_rmc_tag.py ...
1
>>> quit()
[baichuan@zjdw-odmz-0009 python]$ ls
adp_group_info_data  adp_group_info.py  adp_group_info.pyc  db_api.py  db_api.pyc  dump_rmc_area_ip.py  dump_rmc_area_ip.pyc  dump_rmc_tag.py  dump_rmc_tag.pyc
[baichuan@zjdw-odmz-0009 python]$