从导入导入到python解释器主命名空间

Question

How can I run a bunch of imports and path appends from the interpreter with one command/import? If I import another module that runs the commands for me the imports are not available in main namespace. Similar to running a bash script that modifies/adds commands and variables to the current session.

ex.

import os, ...
sys.path.append(...)

Answer 1

If I understand you correctly, you're just looking for the from … import … statement. For example:

lotsostuff.py:

import json
def foo(): pass

Now:

$ python3.3
>>> from lotsostuff import *
>>> json
<module 'json' from '/usr/local/lib/python3.3/json/__init__.py'>
>>> foo
<function lotsostuff.foo>

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However, you might want to consider a different alternative. If you're just trying to control the startup of your interpreter session, you can do this:

$ PYTHONSTARTUP=lotsostuff.py
$ python3.3
>>> json
<module 'json' from '/usr/local/lib/python3.3/json/__init__.py'>
>>> foo
<function __main__.foo>

Notice the difference in the last line. You're now running lotsostuff in the __main__ namespace, rather than running in a separate namespace and grabbing all of its members.

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Similarly:

$ python3.3 -i lotsostuff.py
>>> json
<module 'json' from '/usr/local/lib/python3.3/json/__init__.py'>

You'd normally use PYTHONSTARTUP if you want to do this every time in your session, -i if you want to do it just this once.

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If you want to do the same thing in the middle of a session instead of at startup… well, you can't do it directly, but you can come pretty close with exec (Python 3.x) (or execfile in Python 2.x).

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If you really want to do exactly what you described—importing a module, as a normal import, except merged into your namespace instead of in its own—you'll need to customize the import process. This isn't that hard with importlib ; if you're not in Python 3.2 or later, you'll have a lot more work to do it with imp .

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That's pretty much the difference between . ./foo . ./foo instead of just ./foo in a bash script that I think you were looking for.

If you're using ipython , there are even cooler options. (And if you're not using ipython , you might want to check it out.)