求Mac下Python路径的手动设置方法?

When a module named spam is imported, the interpreter first searches for a built-in module with that name. If not found, it then searches for a file named spam.py in a list of directories given by the variable sys.path. sys.path is initialized from these locations:

• the directory containing the input script (or the current directory).
• PYTHONPATH (a list of directory names, with the same syntax as the shell variable PATH).
• the installation-dependent default.

After initialization, Python programs can modify sys.path. The directory containing the script being run is placed at the beginning of the search path, ahead of the standard library path. [...]

A list of strings that specifies the search path for modules. Initialized from the environment variable PYTHONPATH, plus an installation-dependent default.

As initialized upon program startup, the first item of this list, path[0], is the directory containing the script that was used to invoke the Python interpreter. If the script directory is not available (e.g. if the interpreter is invoked interactively or if the script is read from standard input), path[0] is the empty string, which directs Python to search modules in the current directory first. Notice that the script directory is inserted before the entries inserted as a result of PYTHONPATH.

A program is free to modify this list for its own purposes.

1. 进入 ~/code/django/mysite 之后在命令行下输入 idle 回车，而不是用鼠标去 Application 里点 IDLE。这样一来 IDLE 启动之后的 module 搜索路径就包含当前目录下面的 polls 子目录。
2. 在调用 IDLE 之前设定 PYTHONPATH 环境变量。设定它又有三种方法，均未经验证：
1. 在任意命令行下运行
   PYTHONPATH=/foo/bar idle
   注意这是一行命令。这适用于只需要一次性设定PYTHONPATH的场合，当 idle 结束返回之后，PYTHONPATH也就失效了，不会影响其他程序。
2. 在你的 .bash_profile 或者 .zshrc 里面设定 PYTHONPATH，比如
   export PYTHONPATH=/foo/bar
   这样一来所有从命令行下面启动的 Python 程序都会看到它。
3. 利用 /etc/launchd.conf 设定环境变量，这样一来所系统有 Python 程序，无论是否从命令行下启动，都会看到它。
3. 运行 IDLE 后，手动更改 sys.path，例如
   import sys; sys.path.append('/foo/bar')