Auto-load a module on python startup
I want IPython or the Python interpreter to auto-load a module when I start them.
Is it possible?
For example when I start IPython:
$ ipython
...开发者_如何转开发
>>> from __future__ import division
>>> from mymodule import *
In [1]:
Something like SymPy's live shell found in the tutorial pages.
Have a .pythonstartup
in your home directory and load modules there and point PYTHONSTARTUP
env to that file.
Python commands in that file are executed before the first prompt is displayed in interactive mode.
- http://docs.python.org/using/cmdline.html
I use it for enabling command line completion in python interpreter shell
Unless -S
option is passed to the python
binary, a special site module is imported by default before the execution is passed to your script, or the interactive interpreter. Among other things the module looks for *.pth
files. On each line the *.pth
files should contain either a path to include into sys.path
, or a command to execute. The module as well imports sitecustomize
, and usercustomize
(which can contain arbitrary code, a good way to make your colleagues crazy, if they happen to raise errors) if they exist somewhere in sys.path
.
The problem is though, that the current directory in not in sys.path
when the site
module is imported, that is it is hard to configure your particular script.
I sometimes add the following line at the beginning of my scripts, so that the script would start with searchin for .pth
files in the current directory and adding the missing paths to sys.path
:
# search for *.pth files in the current directory
import site; site.addsitedir('')
Check the file ~/.ipython/ipythonrc
- you can list all modules you want to load at the startup.
Another possible solution is to use the argument -i
from python
interpreter that launches the interaction mode after executing your script.
You could for instance use:
python -i your_module.py
python -i /path/to/your/module
in case you have defined a__main__.py
- or even
python -i -m your.module
To automatically lazily import all top-level importable modules when using them, define this in your PYTHONSTARTUP
file:
import pkgutil
from importlib import import_module
class LazyModule:
def __init__(self, alias, path):
self._alias = alias
self._path = path
globals()[self._alias] = self
def __getattr__(self, attr):
module = import_module(self._path)
globals()[self._alias] = module
return getattr(module, attr)
# All top-level modules.
modules = [x.name for x in pkgutil.iter_modules()]
for module in modules:
LazyModule(alias=module, path=module)
# Also include any other custom aliases.
LazyModule("mpl", "matplotlib")
LazyModule("plt", "matplotlib.pyplot")
LazyModule("pd", "pandas")
LazyModule("sns", "seaborn")
LazyModule("tf", "tensorflow")
Now you can access modules without needing to import them manually:
>>> math.sqrt(0)
0
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