addr i2c detection, re.findall function TypeError. [pull request... *sort of] about lcd

[the-raspberry-pi-guy]

This repository and tutorial is 6 years old @Kyuchumimo, and Python 2.7 support was the norm, especially for the other libraries this is built upon. If you would like to write and support a Python 3 setup then we would be more than happy to incorporate those changes into the repo, as long as it maintains full backwards-compatibility.

[cgomesu]

what's your python version? will take a look at it tomorrow.

…

On Tue, Oct 26, 2021, 8:49 PM Kyuchumimo ***@***.***> wrote: TypeError: cannot use a string pattern on a bytes-like object. drivers/i2c_dev.py 62 ... try: 63 ... self.addr = int('0x{}'.format( 64 ... findall("[0-9a-z]{2}(?!:)", check_output(['/usr/sbin/i2cdetect', '-y', str(BUS_NUMBER)]))[0]), base=16) \ 65 ... if exists('/usr/sbin/i2cdetect') else addr_default This should fix the problem: 62 ... try: 63 ... self.addr = int('0x{}'.format( 64 ... findall("[0-9a-z]{2}(?!:)", check_output(['/usr/sbin/i2cdetect', '-y', str(BUS_NUMBER), encoding='utf8']))[0]), base=16) \ 65 ... if exists('/usr/sbin/i2cdetect') else addr_default — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#33>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AMBRNZDEQHTHCJD2GO4EHLLUI5EAHANCNFSM5GY73UYA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[Kyuchumimo]

what's your python version? will take a look at it tomorrow.

Python 3.7.3, using Thonny IDE

[cgomesu]

Python 3.7.3

the driver was written for (and tested with) Python 2.7, as in the original (Youtube) tutorial and scripts. it may work with Python 3.x but in this particular case, it will raise an error because Python 3 makes a distinction between bytes and strings, whereas Python 2 does not.

This should fix the problem:

62 ... try:
63 ...     self.addr = int('0x{}'.format(
64 ...                       findall("[0-9a-z]{2}(?!:)", check_output(['/usr/sbin/i2cdetect', '-y', str(BUS_NUMBER), encoding='utf8']))[0]), base=16) \
65 ...                       if exists('/usr/sbin/i2cdetect') else addr_default

the use of encoding='utf8' in check_output is a good one for Python 3 but it should be outside the square brackets:

check_output(['/usr/sbin/i2cdetect', '-y', str(BUS_NUMBER)], encoding='utf8')

I'd be happy to push such changes but the problem now is that encoding='utf8' is not supported in the Python 2 version of check_output.

can you think of an alternative that is compatible with both Python 2 and 3?

[Kyuchumimo]

Sorry to put the encoding inside the brackets, it was a typo.

I can think of a solution, but that will be in a few hours, since I am not where I have my Raspberry Pi.
It occurs to me to use a separate function that changes the encoding.

[Kyuchumimo]

Why would you still use python 2.7? Python 2 is deprecated. The latest version to date is Python 3.10

[the-raspberry-pi-guy]

Are we still considering this a bug if this is a Python 3 compatibility issue @cgomesu ? Best to close this issue, or should we leave it open to clearly sign post?

[Kyuchumimo]

It has more to do with compatibility than a bug

[Kyuchumimo]

Done, this should fix the problem.
Works in both Python 2.7 and Python 3.7.3:

addr = int('0x{}'.format(
       findall("[0-9a-z]{2}(?!:)", check_output(['/usr/sbin/i2cdetect', '-y', str(BUS_NUMBER)]).decode())[0]), base=16)

[cgomesu]

Are we still considering this a bug if this is a Python 3 compatibility issue @cgomesu ?

It has more to do with compatibility than a bug

I agree with you both. I added the bug label for quick reference because we do not have custom labels in this repo. I'll take care of that.

Best to close this issue, or should we leave it open to clearly sign post?

Let's wait for a fix from @Kyuchumimo. (See below.)

Done, this should fix the problem.
Works in both Python 2.7 and Python 3.7.3:

addr = int('0x{}'.format(
      findall("[0-9a-z]{2}(?!:)", check_output(['/usr/sbin/i2cdetect', '-y', str(BUS_NUMBER)]).decode())[0]), base=16)

Thanks, @Kyuchumimo. I'll test the implementation when I get back home tomorrow. In the meantime, could you please submit a PR including only this change and linking to this issue?

[cgomesu]

check_output(['/usr/sbin/i2cdetect', '-y', str(BUS_NUMBER)]).decode())[0]

this change is compatible with both Python3 (3.7.3) and Python2 (2.7.16). tested on the following host:

Operating System: Raspbian GNU/Linux 10 (buster)
Kernel: Linux 5.10.63-v7+
Architecture: arm

waiting until the end of the week for @Kyuchumimo to submit a PR to the the-raspberry-pi-guy:master branch. otherwise, I'll submit one on my own, credit them in the commit message, and close this issue (#33) upon merge. please let me know about any objections until then.