Python AttributeError: 'module' object has no attribute 'Serial'

Question

I'm trying to access a serial port with Python 2.6 on my Raspberry Pi running Debian. My script named serial.py tries to import pySerial:

import serial
ser = serial.Serial('/dev/ttyAMA0', 9600)
ser.write("hello world!")

For some reason it refuses to establish the serial connection with this error:

AttributeError: 'module' object has no attribute 'Serial'

When I try to type the same code in the interactive Python interpreter it still doesn't work.

Strangely, it used to work about a couple hours ago.

What could be the problem? I've tried to fix this for a while, installing pySerial again, rewriting my code, double-checking the serial port, etc.

which of these lines doesn't work in interactive Python interpreter ? — Ashwini Chaudhary, Jul 09 '12 at 22:17
@inspectorG4dget no, I haven't done anything with the python version (except re-installing pySerial) — hao_maike, Jul 09 '12 at 22:27
@inspectorG4dget I have the same problem, and I have installed Sphynx (I've uninstalled it since then, but It didn't solve the problem). What could be the fault if you installd a module? — Nearoo, Nov 01 '14 at 15:05
See also http://stackoverflow.com/questions/19728535/serial-import-python — benathon, Feb 06 '15 at 12:09
Please modify what is the correct solution. The one marked by you may have worked on accident, but is neither the solution nor something you want to do. — erikbstack, Apr 16 '16 at 08:24
I deleted the contets of my __pycahe__ folder and it started working. — generic purple turtle, Oct 30 '18 at 20:33
I had the same problem and was fixed by simply changing the file name to something different from 'serial.py' since the code I was running my sample code from matched the library it was looking for the module inside my own test code ! Simple solution to a complicated problem — Ihab, Jun 17 '19 at 01:05

score 221 · Answer 1 · edited Feb 26 '23 at 09:36

221

I'm adding this solution for people who make the same mistake as I did.

In most cases: rename your project file serial.py and delete serial.pyc if exists, then you can simply do import serial without the attribute error.

Problem occurs when you import 'something' when your python file name is 'something.py'.

edited Feb 26 '23 at 09:36

Koedlt

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answered Aug 08 '12 at 21:19

sql

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Yep.. I named my test file "serial.py" so import serial was importing itself.. – PedroMorgan Apr 28 '14 at 03:37
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Additional point for GAE users - try flushing memcache. Somehow ran into this and got stumped for ages after moving a model to a different file. Not sure what was cached that caused it, but it flush fixed it. – OJFord Sep 29 '14 at 20:58
Wow, I never would have come up with this solution, thank you so much. Just sat here staring and indeed, I had an artifact .pyc file that was importing itself. – sofly Jan 29 '15 at 20:38
Really nice! This answer help me a lot, thank you! – Ren Feb 19 '16 at 02:56
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this answer should be #1, I had also the same problem. an alternative appearing error is `AttributeError: 'module' object has no attribute 'SerialException` – user287107 Apr 09 '16 at 22:08
It really helped me. Thank you very much. – User4567 Jun 22 '17 at 10:16
Also, check if there is a (sub)directory called `serial` :-) – handle Jul 03 '17 at 11:20
tanks, i make this mistake – Renato Tavares Feb 26 '18 at 12:35
Removing the `__pycache__` folder fixed the issue for me – Aswin Kumar Jun 02 '19 at 18:15
This is the correct answer to the question that was actually asked. Everything about installing the correct module is irrelevant, or at least belongs on a different question. – Karl Knechtel Aug 01 '22 at 06:53

score 206 · Answer 2 · answered Oct 30 '17 at 13:27

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I accidentally installed 'serial' (sudo python -m pip install serial) instead of 'pySerial' (sudo python -m pip install pyserial), which lead to the same error.

If the previously mentioned solutions did not work for you, double check if you installed the correct library.

answered Oct 30 '17 at 13:27

Kevin

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And the fix is to uninstall both, then reinstall pyserial. – jcaron Feb 20 '18 at 17:39
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Thank you, uninstall serial with `pip uninstall serial` fixed my problem. Then installed pyserial `pip install pyserial` – Dardan Iljazi Mar 16 '18 at 15:07
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Additionally, `pip install --upgrade --force-reinstall pyserial` might help after removing `serial` (or `pip3 ...`). – handle Dec 04 '19 at 09:14
Avoid `sudo pip...`. This will often create files only readable by root and break your python install. Moreover it clutters your global environment. Either `pip install --user` or use [a virtual environment](https://stackoverflow.com/questions/41573587/what-is-the-difference-between-venv-pyvenv-pyenv-virtualenv-virtualenvwrappe) – jozxyqk Dec 13 '21 at 07:38

score 137 · Accepted Answer · edited Oct 28 '18 at 15:01

137

You're importing the module, not the class. So, you must write:

from serial import Serial

You need to install serial module correctly: pip install pyserial.

edited Oct 28 '18 at 15:01

Andrea Corbellini

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answered Jul 09 '12 at 22:21

VGO

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I had the same problem several times while importing modules. I don't understand why it does work in some cases (for instance when you look at some examples in the [*serial* website](http://pyserial.sourceforge.net/shortintro.html)) – VGO Jul 09 '12 at 22:39
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I tried. not work. The error will be "ImportError: cannot import name serial" – Zhang LongQI May 12 '14 at 10:10
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This looks utterly wrong, sorry. At first the class is `Serial` not `serial`, then you don't have to import a class to use it. `module.class()` should work very fine. Last but not least there is no real explanation for what's going on here at all. – erikbstack Apr 16 '16 at 08:22
This does not solve the problem described, and should not have been accepted. It is perfectly okay to import the module rather than the class, because the code then explicitly accesses the class from the module. If the class were imported directly, the rest of the code would have to be modified to match. And again, this *does not change the fact that naming the file `serial.py` causes a problem*. – Karl Knechtel Aug 01 '22 at 06:50
@Kevin the names that PyPI uses for packages do not need to, and often do not, match the "package name" as understood by Python. It is *not a matter of opinion*. The package that you get by using `pip install pyserial`, requires code that says `import serial`, and will not work with code that says `import pyserial`. – Karl Knechtel Aug 01 '22 at 06:51

FutureJJ · Answer 4 · 2018-11-16T12:15:34.447

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You have installed the incorrect package named 'serial'.

Run pip uninstall serial for python 2.x or pip3 uninstall serial for python 3.x
Then install pyserial if not already installed by running pip install pyserial for python 2.x orpip3 install pyserial for python 3.x.

edited Nov 16 '18 at 12:15

answered Mar 22 '18 at 04:35

FutureJJ

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score 2 · Answer 5 · edited May 23 '17 at 12:10

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If you are helpless like me, try this:

List all Sub-Modules of "Serial" (or whatever package you are having trouble with) with the method described here: List all the modules that are part of a python package

In my case, the problems solved one after the other.

...looks like a bug to me...

edited May 23 '17 at 12:10

Community

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answered Nov 01 '14 at 15:16

Nearoo

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It's not clear how this is supposed to solve the problem. We list the modules in the package... and then what? What are "the problems", and *how* were they solved? And how does this relate to the *specific* problem *described in the OP*? – Karl Knechtel Aug 01 '22 at 06:58
@KarlKnechtel This was 8 years ago, I don't remember. But I can read my answer for you: How? No idea. How does this relate to the topic? It solved his/her problem (getting rid of an error message), if it was the same one I had, which appeared to me to be the case. – Nearoo Aug 02 '22 at 10:47

score 1 · Answer 6 · answered Oct 13 '16 at 18:57

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This error can also happen if you have circular dependencies. Check your imports and make sure you do not have any cycles.

answered Oct 13 '16 at 18:57

Chad Zawistowski

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Benjamin · Answer 7 · 2023-03-29T07:07:44.500

Yes this topic is a bit old but i wanted to share the solution that worked for me for those who might need it anyway

As Ali said, try to locate your program using the following from terminal :

 sudo python3
 import serial

print(serial.__file__) --> Copy

CTRL+D #(to get out of python)

sudo python3 -->paste/__init__.py

Running __init__.py will say to your program "ok i'm going to use Serial from python3". My problem was that my python3 program was using Serial from python 2.7

Other solution: remove other python versions

Cao

Sources : https://raspberrypi.stackexchange.com/questions/74742/python-serial-serial-module-not-found-error/85930#85930

Tryhard

This answer is nonsense; there is no such thing as "activating" an `__init__.py` file. — Karl Knechtel, Aug 01 '22 at 06:56

Python AttributeError: 'module' object has no attribute 'Serial'

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