About Us Knowledge Base Community Forum Electronics Toolbox FAQ Shipping & Delivery

Community Forum

Share your projects and post your questions

Search
Register or Sign In
Forum

Pi 3 and PYTHONPATH

2093 Views - Created 13/05/2016

13/05/2016

Posted by:
squiregeek

Users Avatar

Location:
North Carolina, USA

I've installed the ADC board and can run the readvoltage example script under python3. But when I try to run a script of my own, it chokes on from ABE_ADCPi import ADCPi, complaining no such file or directory. Using the file name in the home/pi folder I've added the following lines to /.bashrc:

PATH="${PATH}:home/pi/ABElectronics_python3_libraries/ADCPi"

export PATH

PYTHONPATH="${PYTHONPATH}:home/pi/ABElectronics_python3_libraries/ADCPi"

export PYTHONPATH

ls $PATH and ls $PYTHONPATH both retrun the error: no such file or directory.

What am I missing?

Thanks for your help.

 

13/05/2016

Posted by:
andrew

Users Avatar

Location:
United Kingdom

Users Twitter  Users Website  

Try changing the path to be /home/pi/ABElectronics_Python3_Libraries/ADCPi

Linux is case sensitive so ABElectronics_python3_libraries with a lower case P and L would be seen as a different directory.

AB Electronics UK Tech Support

13/05/2016

Posted by:
squiregeek

Users Avatar

Location:
North Carolina, USA

Thanks, Andrew. The directory added at install is ABElectronics_python3_libraries. Is PATH able to locate ABElectronics_Python3_Libraries?

13/05/2016

Posted by:
squiregeek

Users Avatar

Location:
North Carolina, USA

Andrew,

I went back through the process and founD the git clone you referred to. I put the ABElectronics_Python3_Libraries in $PYTHONPATH in .bashrc and still no joy. I'll try a few variations and see if something will work. Progress...   Jim 

13/05/2016

Posted by:
andrew

Users Avatar

Location:
United Kingdom

Users Twitter  Users Website  

Python 3 should work with PATH.  I just tried setting up a path to the python 3 ADCPi library following our Python Path tutorial and after rebooting and copying the read voltage demo to the root directory I could run the demo and read from the ADC Pi.

AB Electronics UK Tech Support

13/05/2016

Posted by:
squiregeek

Users Avatar

Location:
North Carolina, USA

Andrew, this may be a clue to what I'm doing wrong. I changed the .bashrc entry to PATH="${PATH}:/home/pi/" and ls PATH still showed no file or directory. I'm clearling missing something here. No matter what directory I put in PATH or PYTHONPATH, it shows up when I run ls, but it's not recognized. I'm sure it's something simple, but I just can't see it.

13/05/2016

Posted by:
squiregeek

Users Avatar

Location:
North Carolina, USA

Here's what I get after entering ls:

ls: cannot access :/home/pi/: no such file or directory.

My entry in bashrc is PATH="${PATH}:/home/pi/"

PATH cannot find my home directory. Clearly I've entered something wrong.

14/05/2016

Posted by:
andrew

Users Avatar

Location:
United Kingdom

Users Twitter  Users Website  

Can you try running echo $PATH and see if that returns anything?  On my raspberry pi it is returning 

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/games:/usr/games:/home/pi/Desktop/ABElectronics_Python3_Libraries/ADCPi

while ls PATH does return 

ls: cannot access PATH: No such file or directory

If you try ls /home/pi/ABElectronics_python3_libraries/ADCPi does that go to the correct directory?

Also are you editing the .bashrc file in your home directory or in the root?  In your first post you mentioned /.bashrc .  It should be the file in your home directory ~/.bashrc that you need to edit which you can get to with

sudo nano ~/.bashrc

AB Electronics UK Tech Support

14/05/2016

Posted by:
squiregeek

Users Avatar

Location:
North Carolina, USA

Andrew,

I ran 'echo $PATH' and it returned the complete path without errors. 'echo $PYTHONPATH' also worked. I still was unable to run /home/pi/demo-readvoltage.py from the terminal but could from IDLE. I've been using 'sudo python3 demo-readvoltage.py' because an earlier version of the script used GPIO under Wheezy (no longer needed under Jessie). When I dropped the 'sudo' both the demo program from examples and my test script worked.

I suspect that improper use of 'sudo' was the root of my problem. Perhaps it was referencing root's bashrc. Using 'ls $PATH' (as suggested on a couple of forums) instead of 'echo $PATH' led me astray. I am deeply grateful for your help. My project is back on track thanks your patient help.

Note: documents in Portable Document Format (PDF) require Adobe Acrobat Reader 5.0 or higher to view, download Adobe Acrobat Reader or other PDF reading software for your computer or mobile device.