技术小黑屋

Check if a Python Module Is Installed

I was once stucked in How to check Whether a Python module has been installed or not. After Googling, I found this trick.
Python allows user to pass command from out of a python file.See here

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-c cmd : program passed in as string (terminates option list)

The result if we import an installed module

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20:15:45-androidyue~/osc_git/LnxClient (master)$ python -c "import os"
20:31:24-androidyue~/osc_git/LnxClient (master)$ echo $?
0
#0 means the module has been installed

Now if we import an module which is not installed.

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20:31:41-androidyue~/osc_git/LnxClient (master)$ python -c "import aaa"
Traceback (most recent call last):
File "<string>", line 1, in <module>
ImportError: No module named aaa
20:31:46-androidyue~/osc_git/LnxClient (master)$ echo $?
1
#1 means that module is not installed.

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