Using Point Cloud Library in Python - c++

Hello I am trying to use Point Cloud Library in Python and as I am new to this C++ library and Python I am following the tutorial on http://strawlab.github.io/python-pcl/#pcl.PointCloud
However whenever I try to import pcl and define a module such as pcl.PointCloud() I get the following error;
AttributeError: 'module' object has no attribute 'PointCloud'
I have used sys.path.append to point to the correct directory where the PCL files have been installed as they are not in site packages. It says on the above link that the C++ code has already got Python bindings but I am unsure exactly what files I am trying to call in Python. Does anybody know how to overcome this error and load these modules?
Thanks,
Andrew

Try this,
sudo add-apt-repository ppa:sweptlaser/python3-pcl
sudo apt update
sudo apt install python3-pcl
After you've done that then you should be able to run:
python3 -c 'import pcl'
and it will return with no error (as opposed to ModuleNotFoundError: No module named 'pcl').
Tested on:
Ubuntu 18.04 LTS
Python 3.6.9
Reference: https://askubuntu.com/a/1170661/922137

Try skipping the parentheses:
from pcl import PointCloud
And then create an instance of PointCloud, for example, p:
p = PointCloud()
Hope it helps!

Looks like you need PCL 1.5.1 and cython 0.16 according to this page: http://strawlab.github.io/python-pcl/

"""https://blog.pollithy.com/python/numpy/pointcloud/tutorial-pypcd"""
python3.6 -m pip install --user git+https://github.com/DanielPollithy/pypcd.git

Related

python - pip installs but cannot import

I've read a lot of posts about this but none of the solutions have worked for me. I'm trying to get a module called nsxramlclient installed, shows successful installation with pip but cannot import from any location outside of the /Users/Nathan/Library/Python/2.7/lib/python/site-packages.
Uninstall does work after some fidgeting with brew using the recommendations found with brew doctor. Here are some vitals:
Running OSX python 2.7.10
PIP 18.1
which -a pip = /usr/local/bin/pip
which -a python = shows 2 directories:
/usr/local/bin/python
/usr/bin/python
python -c 'import sys; print(sys.path)'
['', '/usr/local/Cellar/python#2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python27.zip', '/usr/local/Cellar/python#2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7', '/usr/local/Cellar/python#2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin', '/usr/local/Cellar/python#2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac', '/usr/local/Cellar/python#2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages', '/usr/local/Cellar/python#2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk', '/usr/local/Cellar/python#2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-old', '/usr/local/Cellar/python#2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload']
pip list | grep nsxramlclient
nsxramlclient 2.0.7
It has to be a path issue since I'm able to import it from the directory that the module is located. I just don't know the proper method to repair this since I'm fairly new to Python and I don't want to mess it up worse that it is already.
Looks like I did end up getting it to work finally. What I had to do was to re-install python with brew:
brew re-install python#2
then I needed to re-install the modules I needed with pip. Having OTHER issues now but at least this one is fixed.

nltk module installation in pip through cmd

When I tried to run this command:
c:\python27\scripts\pip install nltk-3.2.1-py2.py3-none-any
I am getting the error:
no matching distribution found
Although i have installed nltk from
http://www.lfd.uci.edu/~gohlke/pythonlibs/#nltk
Kindly help.
I am working on Windows 8 64-bit Version
Installing new modules can be a nightmare if you are new to Python.First delete any old versions of NLTK if already installed. Open cmd navigate to C:\Users\user\AppData\Local\Programs\Python\Python35-32\Scripts, the default directory, using the command cd path_name_comes_here. Otherwise goto the path where you have installed python and goto the Scripts subfolder and use this path here onwards. Now the most preferred way is to use pip install module_you_want_to_install for anything in python. Pip automatically fetches everything it needs to install said module.
Simply use pip install nltk.
Another method is to use easy_install requirement_or_URL.
Some rare occasions its best to download the wheel from http://www.lfd.uci.edu/~gohlke/pythonlibs and from there you can simply use pip install downloaded_wheel_name again. But make sure to copy the name of the wheel EXACTLY.
Post installation make sure that your package is accessible from C:\Users\user\AppData\Local\Programs\Python\Python35-32\Lib\site-packages or a similar path depending on where you installed python.
Try Anaconda - Instead . Always works
C:\Users\sanan>conda install -c anaconda nltk
Fetching package metadata .............
Solving package specifications: .
Package plan for installation in environment C:\Users\sanan\Miniconda3:
The following NEW packages will be INSTALLED:
nltk: 3.2.4-py36_0 anaconda
The following packages will be UPDATED:
conda: 4.3.23-py36_0 --> 4.3.25-py36_0 anaconda
The following packages will be SUPERSEDED by a higher-priority channel:
conda-env: 2.6.0-0 --> 2.6.0-0 anaconda
Proceed ([y]/n)? y
conda-env-2.6. 100% |###############################| Time: 0:00:00 22.84 kB/s
nltk-3.2.4-py3 100% |###############################| Time: 0:00:02 774.24 kB/s
conda-4.3.25-p 100% |###############################| Time: 0:00:00 578.90 kB/s
After installation is complete .
import nltk
print(nltk.__version__)
C:\Public\Code\textnorm>python attempt1.py
3.2.4

robot framework installation on ubuntu selenium2library cannot

Hi i tried to install Rf on ubuntu(VM box) like here:
http://testingknols.blogspot.com/2014/05/robot-framework-installation-on-ubuntu.html
but problem is with selenium2library.
when I am using "S python" i got the message in termina "command not found"
when I am using:
import Selenium2Library I can see:
he program 'import' can be found in the following packages:
* imagemagick
* graphicsmagick-imagemagick-compat
Try: sudo apt-get install
what should I do?
My python version is 2.7.6
I don't know what is "S python".
I just installed the selenium2library. You can install it using the console with:
$ pip install robotframework-selenium2library
Then you can use this library in your .robot file importing it, writing inside the setting block of the test:
Library Selenium2Library

ImportError: No module named twisted.internet

I installed python 2.7.5 which is working fine.
I then install scrapy (which, I think, uses twisted internally). My scrapy spider is also working fine.
I installed twisted:
sudo apt-get install python-twisted
Then, I created a sample program using Echo Server code shown here
Here is the code
from twisted.internet import protocol, reactor
class Echo(protocol.Protocol):
def dataReceived(self, data):
self.transport.write(data)
class EchoFactory(protocol.Factory):
def buildProtocol(self, addr):
return Echo()
reactor.listenTCP(1234, EchoFactory())
reactor.run()
I try to run this code using this command:
$ python twistedTester.py
Traceback (most recent call last):
File "twistedTester.py", line 1, in <module>
from twisted.internet import protocol, reactor
ImportError: No module named twisted.internet
Can anyone help me with how I can debug why my twisted package is not being picked up by Python installation?
If you use pip just try:
pip install twisted
The same works with w3lib and lxml.
On some *nix systems this might give you a permission error. If that happens, try:
sudo -H pip install twisted
I figured out why this error was happening. For some reason, using apt-get to install a python package was not installing it right.
So, I had to download a tar ball and install the package from them.
I downloaded Twisted tar from here.
I did a tar xjf Twisted-13.1.0.tar.bz2 - this created a directory called Twisted-13.1.0
next, cd Twisted-13.1.0
Finally, python setup.py install
This gave me an error. Twisted required another package called zope.interface. So, I downloaded tar ball for zope.interface from here. Then, ran this command tar xzf zope.interface-3.6.1.tar.gz That created a folder called zope.interface-3.6.1. So, cd into zope.interface-3.6.1 and run python setup.py install
Note: Depending on your user's rights, you may want to do these commands in sudo mode. Just add the keyword sudo before every command.
please rename the file twisted.py to something else. whenever you import a function from a file the interpreter will search for the file in the current location and then it searches in the library. so if you have any file in the name of "twisted.py" you should probably rename it.
after renaming it. dont fail to remove the twisted.pyc file before running it again.
It happened to me too. Finally I figure out that there is a file named twisted.py my present working directory. I removed twisted.py and twisted.pyc. Problem resolved.
Looks like Twisted may have removed the twisted.internet module from the current release. Pinning on the version required by scrapy (17.9.0) worked for me:
$ pip install twisted==17.9.0
Checking if it's installed:
$ python -c "import twisted.internet; print(twisted.internet)"
<module 'twisted.internet' from '/Users/username/dev/env/redacted-ewmlD2h2/lib/python3.7/site-packages/twisted/internet/__init__.py'>
I figured out why apt-get install python-twisted was not enough or "installing it right", as you said, user1700184.
I use Debian Wheezy and Python 2.7.
I just had to move the folder named "twisted" from /usr/lib/python2.7/dist-packages/ to /usr/lib/python2.7/
The same has to be done with the package "zope" and any other one that you do install but is not retrieved when you try run your code.
However, why this is even necessary in my case is still a mystery since my sys.path does include both /usr/lib/python2.7/ and /usr/lib/python2.7/dist-packages, so whatever was under dist-packages should have been retrieved by the interpreter.
I think it is worth noting that if you use sudo to launch python you are using your original default system python. This is NOT the python that your PATH points to. For example if you are using Anaconda and you have updated your path such that which python points to path/to/anaconda/bin/python, sudo which python will still point to usr/bin/python.
So obviously sudo python twistedTester.py will not find the twisted module. To get around this you should explicitly pass the path to the anaconda python. Like so:
sudo path/to/anaconda/bin/python twistedTester.py

"ImportError: ... Expected in: flat namespace" when setting up a mysql database

mySQL seems to be up and running just fine. But when I try to import MySQLdb into python I get a ImportError: ... Expected in: flat namespace. I think it has to do with having two different versions for python (well two different directories, same version)
OS: Mac 10.6.8
$ ls /Library/Frameworks/Python.framework/Versions/
7.2 Current
$ which python
/Library/Frameworks/Python.framework/Versions/Current/bin/python
$ echo $PATH
/Library/Frameworks/Python.framework/Versions/Current/bin:/Library/Frameworks/Python.framework/Versions/2.7/bin:/Library/Frameworks/Python.framework/Versions/2.7/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin:/usr/X11/bin
$ easy_install MySQL-python
...
...
Using /Library/Frameworks/Python.framework/Versions/7.2/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.5-i386.egg
...
$ mysql.server start
Starting MySQL
.. SUCCESS!
$ python manage.py runserver
...
...
django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: dlopen(/Library/Frameworks/Python.framework/Versions/7.2/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.5-i386.egg/_mysql.so, 2): Symbol not found: _mysql_affected_rows
Referenced from: /Library/Frameworks/Python.framework/Versions/7.2/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.5-i386.egg/_mysql.so
Expected in: flat namespace
in /Library/Frameworks/Python.framework/Versions/7.2/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.5-i386.egg/_mysql.so
$ python
Enthought Python Distribution (EPD) free version -- www.enthought.com
Version: 7.2-2 (32-bit)
>>> import MySQLdb
...
...
ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/7.2/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.5-i386.egg/_mysql.so, 2): Symbol not found: _mysql_affected_rows
Referenced from: /Library/Frameworks/Python.framework/Versions/7.2/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.5-i386.egg/_mysql.so
Expected in: flat namespace
in /Library/Frameworks/Python.framework/Versions/7.2/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.5-i386.egg/_mysql.so
So in addition to being new to django and python I'm also new to using the terminal, and I'm not exactly sure what I'm looking at.
But I can tell the obvious:
I have two versions, 7.2 and current.
If I call python it will call the 'Current' version. That makes sense, it's in $PATH.
However, a version 2.7 (not 7.2) is also in PATH which I had deleted when I installed the EDP package. ...I don't fully understand what PATH is or does so I didn't want to start changing things
MySQL-python is installed in version 7.2
Can't run the server because a necessary file isn't in flat namespace and it's at the place it was installed too
Is there some way to untangle these paths (if that's the problem)
thank you in advance
Well... I don't think it had anything the do with the "Current" and "7.2" versions of python.
It seems to have fixed itself after doing
pip uninstall MySQL-python
brew uninstall mysql
brew install mysql --universal
pip install MySQL-python
I'm not sure if the --universal made the diference or using pip install as opposed to easy_install