sys.modules

DL Neil PythonList at DancesWithMice.info
Thu Feb 21 14:32:19 EST 2019


Hello,


On 22/02/19 5:40 AM, ast wrote:
> Is it normal to have 151 entries in dictionary sys.modules
> just after starting IDLE or something goes wrong ?
>  >>> import sys
>  >>> len(sys.modules)
> 151

I don't use Idle. Written in python, doesn't it require various packages 
to run before it even talks to you, eg tkinter? Thus am not sure if they 
are also being counted. However:-

After firing-up Python 3.7 from the cmdLN, my system reported only 60.

Remember also, that the sys Run-time service is described as 
"System-specific parameters and functions", which will account for 
(some) differences by itself.


> Most of common modules seems to be already there,
> os, itertools, random ....
> I thought that sys.modules was containing loaded modules
> with import command only.

Not quite true! Whereas the manual says
<<<
sys.modules This is a dictionary that maps module names to modules which 
have already been loaded.
 >>>

also remember that import is not the only way modules are "loaded"! 
Built-in types (etc) are/must be loaded as part of python, otherwise 
nothing would work, eg float, int, list, contextlib, collections, 
functools, ... This is the modular/boot-strap method that is a feature 
of python.

Web-refs:
https://docs.python.org/3/tutorial/modules.html#standard-modules
https://stackoverflow.com/questions/7643809/what-are-default-modules-in-python-which-are-imported-when-we-run-python-as-for

-- 
Regards =dn


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