I am new to ROS,
I have a problem when I import rospy into my script file example.py and run it: It says:
Traceback (most recent call last):
File "/home/nagarjunv/hk_ws/src/rvo/src/example.py", line 4, in <module>
import rospy
File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/__init__.py", line 49, in <module>
from .client import spin, myargv, init_node, \
File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/client.py", line 52, in <module>
import roslib
File "/opt/ros/melodic/lib/python2.7/dist-packages/roslib/__init__.py", line 50, in <module>
from roslib.launcher import load_manifest # noqa: F401
File "/opt/ros/melodic/lib/python2.7/dist-packages/roslib/launcher.py", line 42, in <module>
import rospkg
ModuleNotFoundError: No module named 'rospkg'
I am importing the following into my script file:The line 4 is rospy
#!/usr/bin/env python3
import sys
import rospy
THis is my CmakeLists:
cmake_minimum_required(VERSION 3.0.2)
project(rvo)
find_package(catkin REQUIRED COMPONENTS
rospy
std_msgs
message_generation
)
generate_messages(
DEPENDENCIES
std_msgs
)
catkin_package(
# INCLUDE_DIRS include
# LIBRARIES rvo
CATKIN_DEPENDS rospy std_msgs
# DEPENDS system_lib
)
include_directories(
# include
${catkin_INCLUDE_DIRS}
)
This is my package xml:
<buildtool_depend>catkin</buildtool_depend>
<build_depend>rospy</build_depend>
<build_depend>std_msgs</build_depend>
<build_depend>message_generation</build_depend>
<build_export_depend>rospy</build_export_depend>
<build_export_depend>std_msgs</build_export_depend>
<build_export_depend>message_generation</build_export_depend>
<exec_depend>rospy</exec_depend>
<exec_depend>std_msgs</exec_depend>
<exec_depend>message_runtime</exec_depend>
I specify both in CMakelists and Package XML 'rospy' and importing it. I also checked my ros has rospy package available. BUt, I dont understand why I am having trouble running my script file?
rosrun rvo example.py
I will be glad to provide more details about this error. Can any please let me know the solution to this problem?
Try to change the shebang (line 1) according to the python version your ROS distro works with.
For melodic or earlier: #!/usr/bin/env python2
For noetic or later: #!/usr/bin/env python3
Depending on your ROS version and respectively the one of rospkg you may need to stick to python 2.x or 3.x.
Your script is calling python3 interpreter
#!/usr/bin/env python3
but you can clearly see in the error log that a different version is used by your installation:
File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/init.py",
line 49, in
from .client import spin, myargv, init_node, \
If you want to use Python 3 for a ROS installation that is based on Python 2.7 you need to build everything from scratch but even then the chances for success are pretty slim.
Here are some possible solution:
If you want to use Python 3, see here. According to this article ROS Noetic is targeting only Python 3.
If you don't want to upgrade, you need to stick to Python 2.7.
If the version of Python is of no concern, just adapt your script to use the one your ROS installation is depending on.
Related
I want to make a Yocto image for my hardware (i.e. IMX8) according to this manual:
https://github.com/compulab-yokneam/meta-bsp-imx8mm/blob/iot-gate-imx8_r3.1/README.md
I installed python3, and python2 on my Linux (Ubuntu 22.04) that is run on on VMWare virtual machine.
I configure my python using update-alternatives and I can alter and check the Python version, and every thing is correct. But I encounter with the following message when I run the bitbakecommand:
Traceback (most recent call last):
File "/home/sap1359/compulab/sources/poky/bitbake/bin/bitbake", line 19, in <module>
import bb
File "/home/sap1359/compulab/sources/poky/bitbake/lib/bb/__init__.py", line 128, in <module>
from bb import fetch2 as fetch
File "/home/sap1359/compulab/sources/poky/bitbake/lib/bb/fetch2/__init__.py", line 26, in <module>
import bb.persist_data, bb.utils
File "/home/sap1359/compulab/sources/poky/bitbake/lib/bb/persist_data.py", line 22, in <module>
from collections import Mapping
ImportError: cannot import name 'Mapping' from 'collections' (/usr/lib/python3.10/collections/__init__.py)
When I try to track another tutorial for other hardware or even for a simple X86 Yocto image,there is something the same as this error cannot import name 'someting' from 'collections'.
I also tried using virtualenv and setting up an virtual environment, however, the Import error persist.
I checked using Ubuntu 18.04, everything was OK.
According to my tests, this Yocto project can't work with Python3.10 and above, however, works in Ubuntu 22.04 by installing another version of Python3 such as 3.8.
I just want to mention that this Yocto source just uses Python3.5, or above.
Running a locust (locust.io) script from the command line.
locust calls main.py which has the following imports:
from locust import HttpUser, between, task
from StreamLoader.stream_generator import * # thought this brings in everything
Packer.py has these imports:
from multipledispatch import dispatch
from PackedItem import PackedItem
StreamGenerator.py has:
import hashlib
from StreamLoader.Packer import Packer
from aes_encryption import AesEncryption
I used pip to install multipledispatch and when I run from within PyCharm it works fine, but from the command line I get the following.
File "C:\Users\guyl\PycharmProjects\engine-load-tests\engine_load_tester_locust\main.py", line 2, in <module>
from StreamLoader.stream_generator import *
File "C:\Users\guyl\PycharmProjects\engine-load-tests\StreamLoader\stream_generator.py", line 2, in <module>
from StreamLoader.Packer import Packer
File "C:\Users\guyl\PycharmProjects\engine-load-tests\StreamLoader\Packer.py", line 1, in <module>
from multipledispatch import dispatch
ModuleNotFoundError: No module named 'multipledispatch'
Here is what I have tried so far:
Add directories to the PYTHONPATH environment variable
Add empty __init__.py files in each package
This all seems unnecessary if I actually pip installed the module, though.
Answer below caused me to no longer see the error with multipledispatch. However, I now see a missing module error:
File "C:\Users\guyl\PycharmProjects\engine-load-tests\engine_load_tester_locust\main.py", line 2, in <module>
from StreamLoader.stream_generator import *
File "C:\Users\guyl\PycharmProjects\engine-load-tests\StreamLoader\stream_generator.py", line 2, in <module>
from Packer import Packer
ModuleNotFoundError: No module named 'Packer'
For clarity, I am running the code from locust which calls the Python code as depicted here. [Moderators - this question is getting quite long. Is that all right?]
PyCharm uses the virtual environment automatically but when you run from the command line the virtual environment isn't turned on.
Just follow the steps:
cd your_working_directory
environment_name/Scripts/activate if on Windows where environment_name is the name of the PyCharm virtual environment
Or environment_name/bin/activate if on MacOS
-------------EDIT------------------------
To answer the new question, try using pip freeze then see which packages are installed. Then install any dependencies which you want which are missing.
I am unable to run a python script in the command line, and this script works great in Jupyter Notebook and via Anaconda Prompt. This appears to be an issue importing the ssl module during initialization of another module I am importing (mygeotab).
I have googled the error and done as much as I can to diagnose the most common cause which appears to be PATH issues.
I have already diagnosed the PATH to a point, and have added the location of the /lib/ and python.exe to the environment variables. Also, during testing I began my script with the below to protect myself from path issues and printed the path before and after the 'append', which did not have an impact on the problem.
import sys
print(sys.path)
sys.path.append('C:\\Users\\xxxxxx\\Python Scripts')
sys.path.append('C:\\Anaconda3\\python37.zip')
sys.path.append('C:\\Anaconda3\\DLLs')
sys.path.append('C:\\Anaconda3\\lib')
sys.path.append('C:\\Anaconda3')
sys.path.append('C:\\Anaconda3\\lib\\site-packages')
sys.path.append('C:\\Anaconda3\\lib\\site-packages\\win32')
sys.path.append('C:\\Anaconda3\\lib\\site-packages\\win32\\lib')
sys.path.append('C:\\Anaconda3\\lib\\site-packages\\Pythonwin')
sys.path.append('C:\\Anaconda3\\lib\\site-packages\\IPython\\extensions')
sys.path.append('C:\\Users\\xxxxxx\\.ipython')
sys.path.append('C:\\Anaconda3\\Lib')
sys.path.append('C:\\Anaconda3\\Lib\\site-packages')
print(sys.path)
import mygeotab
import pandas as pd
import pyodbc as py
from mygeotab.ext import feed
import sqlalchemy
from time import sleep
However, when I attempt to run the script via the standard command line, I get the below error:
Traceback (most recent call last):
File "PYTHON_GEOTAB_TRIP_FEED.py", line 33, in <module>
import mygeotab
File "C:\Anaconda3\lib\site-packages\mygeotab\__init__.py", line 9, in <module>
from .api import Credentials
File "C:\Anaconda3\lib\site-packages\mygeotab\api.py", line 14, in <module>
import ssl
File "C:\Anaconda3\lib\ssl.py", line 98, in <module>
import _ssl # if we can't import it, let the error propagate
ImportError: DLL load failed: The specified module could not be found.
The mygeotab module and ssl.py are both in the locations designated in the Traceback. '_ssl' is the only reference I can not seem to diagnose. Again, this works fine in both Notebook and Anaconda Prompt.
Any ideas?
Windows Server 2008 R2
Anaconda 2019.07 x64
Python 3.7.3 x64
This was solved for me by installing a separate instance of Python 3.7, moving the PATH references and other pointers. I installed pip, mygeotab, and the other packages into the native Python 3.7 instance. It just appears you can't use the one baked into anaconda the way I thought. Thanks for the help everyone.
I am working in Ubuntu 14.04 and I have multiple versions of Python on my machine (they include python2.7 and python3.4). Few days back, I installed simplejson on my system. I don't remember how I did that but I guess it must be similar to pip install simplejson. However, now a strange problem has started appearing when I try installing any python package. For example, just now I tried installing Tkinter using sudo pip3.4 install Tkinter and it throws the following error:
Traceback (most recent call last):
File "/usr/local/bin/pip3.4", line 9, in <module>
load_entry_point('pip==1.5.4', 'console_scripts', 'pip3.4')()
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 351, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 2363, in load_entry_point
return ep.load()
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 2088, in load
entry = __import__(self.module_name, globals(),globals(), ['__name__'])
File "/usr/lib/python3/dist-packages/pip/__init__.py", line 61, in <module>
from pip.vcs import git, mercurial, subversion, bazaar # noqa
File "/usr/lib/python3/dist-packages/pip/vcs/subversion.py", line 4, in <module>
from pip.index import Link
File "/usr/lib/python3/dist-packages/pip/index.py", line 15, in <module>
from pip.wheel import Wheel, wheel_ext
File "/usr/lib/python3/dist-packages/pip/wheel.py", line 25, in <module>
from distlib.scripts import ScriptMaker
File "/usr/share/python-wheels/distlib-0.1.8-py2.py3-none-any.whl/distlib/scripts.py", line 15, in <module>
File "/usr/share/python-wheels/distlib-0.1.8-py2.py3-none-any.whl/distlib/resources.py", line 20, in <module>
File "/usr/share/python-wheels/distlib-0.1.8-py2.py3-none-any.whl/distlib/util.py", line 11, in <module>
ImportError: No module named 'json'
Sometimes I can fix this if the error tells me that in one of the files I have:
import json
which I simply convert to
import simplejson as json
I tried uninstalling simplejson:
sudo pip uninstall simplejson
but it gives me the same error: json not found.
Can anybody please help me fix this so that I would happily be able to install python packages? Thanks in advance.
Note: I do not have a definitive answer but will offer a series of steps you can try:
The first thing is see if you can import json from the usual python interpreter:
import json
print(json.__file__) #this would be important to know if it works
If that does work (as well as commenting what json.__file__ is) you would then want to try to use pip from the interpreter.
If you can't import json normally:
This is not surprising, I did not expect pip to be looking in a non-standard place for modules. You will want to figure out where the json package should be located on your computer, you can do this by importing another module from the standard library and looking at it's __file__:
>>> import fractions
>>> fractions.__file__
'/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/fractions.py'
This will obviously be different for you but I'd expect there to be a json folder in the same folder as fractions.py
if you can't import fractions or queue or datetime etc.
If you can't import anything from the standard library you will probably want to just reinstall python.
If the json folder is there and contains an __init__.py
Use the rename function of your file browser to make sure there are no weird special characters, but other then that I'm not sure, if you can import fractions.py but not a package from the same folder that would imply there is something very wrong with the import mechanics of your python version.
If the json folder is not with the rest of the standard library
It is possible that your python distribution has a different structure then I'd expect, it at least can't hurt to take a look for it.
You can search for the json folder amongst your various python files using the find command, not really sure how it works but just another thing to try. If you do find it with the __init__.py, encode.py, decode.py, scanner.py, and tool.py (at least those are the ones in my version) you'll probably want to figure out how it got there, but maybe just move it to the same folder as the rest of the standard library.
If you can't find the json package or you find it and it is corrupted
Well then you will need to replace it! Don't worry, this isn't too hard, just grab a source release of python from the site and extract the json package from it, once it is uncompressed the json folder should be in the Lib folder. Simply copy/move it to the rest of the standard library and you should be good to go!
I hope this helps you debug what is going on, This covers all the scenarios I could imagine happening and I would be interested in which one fixed your issue (or what you were able to figure out so I can come up with more options)
I am guessing that you install it using either pip install simplejson to download from PyPI or using apt-get install python-simplejson to download from ubuntu repositories.
It is possible that you downlaoded the library for the Python2 if you used any of the commands above and it won't be available for Python3 (which pip3.4 will use). Can you try these commands and help debug yourself?
$ python -c "import simplejson"
$ python3.4 -c "import simplejson"
This would tell you which version of the python did you install simplejson for last time (my guess in python2). If the 2nd command errors out with ImportError try:
$ pip3.4 install simplejson
and then install your libraries.
I'm trying to configure and run SVN post-commit hook sending mails. I've downloaded class mailer.py, installed Python 2.7 and svn-win32 bindings for svn. The machine is Windows-7 64 bit, the Python is 32 bit. Now the mailer.py ends with error, which is caused by import problem.
When I in python console type "import svn.core" I have following error:
>>> import svn.core
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "c:\tools\Python27\lib\site-packages\svn\core.py", line 19, in <module>
from libsvn.core import *
File "c:\tools\Python27\lib\site-packages\libsvn\core.py", line 5, in <module>
import _core
ImportError: No module named _core
while in directory site-packages/libsvn are files such as: _core.dll
I've installed other bindings, pysvn, that was installed correctly, but as far as I've noticed, it's the totally other API so I can't use that for python.py
Does someone had similar problem and knows how to deal with it?
The Python bindings need to load the native Subversion libraries (DLL's). If your Python is 32-bit then you would need 32-bit versions of the native Subversion libraries on PATH.
I have problem like this. Trouble was that python just can not import this library (svn.core and other).
I just make:
import sys
sys.path.append("C:\csvn\lib\svn-python").
My file core.pyc was in C:\csvn\lib\svn-python\svn. Hope it helps somebody. Such behacior for me is strange because there is no "init.py" or "init.pyc" file in svn-python directory. But it works.