Why is this happening:
$ python3
Python 3.1.2 (release31-maint, Dec 9 2011, 20:50:50)
[GCC 4.4.5] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import argparse
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named argparse
I installed python3 precisely because I wanted to use argparse, which was new in 2.7, and the default version on Ubuntu Server 10.04 is 2.6.
Another thing I've noticed: Mint 10 comes with python 2.6.6, which does include argparse, and the exact version that ships with ubuntu-server 10.04 is 2.6.5 which does not have argparse. Also, I've noticed that on my Ubuntu 12.04 machine python3 is 3.2.3 and this does come with argparse. Why would this module not be included with 3.1.x???
Although argparse only made it into the standard lib on Python 2.7 and Python 3.2, for older/other versions you can still get it from pypi.
Keep in mind though that this version may not include all the updates that happened since the merge of argparse to the standard lib (as it's explained on the original project's webpage).
Related
When trying to install pgadmin4 in desktop mode on my Ubuntu system, I received a ModuleNotFoundError for _ctypes.
I did some research and found that _ctypes requires the libffi-dev package to be installed. However it seems that libffi-dev and thus _ctypes was installed for Python 2.7, when I run import ctypes it seems to work:
$ python2
Python 2.7.15+ (default, Nov 27 2018, 23:36:35)
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import ctypes
>>>
When I try to do the same for Python 3.7, it doesn't work:
$ python
Python 3.7.3 (default, Jun 21 2019, 12:46:58)
[GCC 7.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import ctypes
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python3.7/ctypes/__init__.py", line 7, in <module>
from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named '_ctypes'
How could I add the module _ctypes to my Python 3.7 configuration?
If you install python from source file, you have to install some required packages manually as mentioned in https://superuser.com/questions/1412975/how-to-build-and-install-python-3-7-x-from-source-on-debian-9-8.
Actually you are supposed to see some errors after make due to libffinot found as shown in the screenshot below. However, you can still run make install despite the error. When you open python after the installation and import the module, it then gives you such error.
To solve this problem, you can install the dependent package i.e libffi or libffi-devel(redhat) prior to ./configure, make and make install as mentioned in:
Package libffi was not found in the pkg-config search path REDHAT6.5 and
https://bugs.python.org/issue31652.
I have installed graph-tool:
brew --prefix graph-tool
'/usr/local/opt/graph-tool
but when trying to import it:
Python 3.6.4 |Anaconda, Inc.| (default, Jan 16 2018, 12:04:33)
[GCC 4.2.1 Compatible Clang 4.0.1 (tags/RELEASE_401/final)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from graph_tool.all import *
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'graph_tool'
:(
Does anyone have a solution for this?
Thanks
Homebrew installs the library using its own Python interpreter, which has its module path somewhere in /usr/local/opt/. You are using the anaconda Python interpreter, which knows nothing about homebrew-installed modules. The solution here is simply to use homebrew's Python interpreter, not anaconda's.
The command line application shoogle (https://github.com/tokland/shoogle) which exposes google api services at a terminal command line requires python3 but the ubuntu 16 default python is 2.7.
I have tried alias and calling the shoogle app from subprocess in a python3 shell but (of course) the os still provides the default. I have been reluctant to make system wide changes to .bashrc or PYTHONPATH e.g. as so many other resource expect 2.7. But I am currently using this on a virtual machine so if it does break I can recover. That seems the only option but impractical in a production environment.
I've found very little shoogle help online (the author suggests SO etc. for support) so if any one has any experience with shoogle or suggestions to get the requiured python version I'd be happy to hear.
Running shoogle from a python3 interpreter finds the 2.7 files:
3.5.2 (default, Nov 23 2017, 16:37:01)
[GCC 5.4.0 20160609]
Python Type "help", "copyright", "credits" or "license" for more information.
from subprocess import call
call (['shoogle', 'show'])
Traceback (most recent call last):
File "/usr/local/bin/shoogle", line 11, in <module>
import shoogle
File "/usr/local/lib/python2.7/dist-packages/shoogle/__init__.py", line 5,
in <module> from .shoogle import *
File "/usr/local/lib/python2.7/dist-packages/shoogle/shoogle.py", line 14, in <module>
from . import commands
File "/usr/local/lib/python2.7/dist-packages/shoogle/commands/__init__.py", line 2, in <module>
from . import execute
Using #Surest Texans suggestions I uninstalled the shoogle app and used pip3 install to reinstall. Now the application works as expected when called from the command line.
I am on CentOs7. I installed tk, tk-devel, tkinter through yum. I can import tkinter in Python 3, but not in Python 2.7. Any ideas?
Success in Python 3 (Anaconda):
Python 3.6.3 |Anaconda custom (64-bit)| (default, Oct 13 2017, 12:02:49)
[GCC 7.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tkinter
>>>
But fail on Python 2.7 (CentOS default):
Python 2.7.5 (default, Aug 4 2017, 00:39:18)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-16)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import Tkinter
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib64/python2.7/lib-tk/Tkinter.py", line 39, in <module>
import _tkinter # If this fails your Python may not be configured for Tk
ImportError: libTix.so: cannot open shared object file: No such file or directory
I read some answers said
If it fails with "No module named _tkinter", your Python configuration needs to be modified to include this module (which is an extension module implemented in C). Do not edit Modules/Setup (it is out of date). You may have to install Tcl and Tk (when using RPM, install the -devel RPMs as well) and/or edit the setup.py script to point to the right locations where Tcl/Tk is installed. If you install Tcl/Tk in the default locations, simply rerunning "make" should build the _tkinter extension.
I have reinstalled tk, tk-devel and tkinter through yum, but the problem is same.
How can I configure it to work on Python 2.7?
For python 3 use:
import tkinter
For python 2 use:
import Tkinter
If these do not work install with, for python 3:
sudo apt-get install python3-tk
or, for python 2:
sudo apt-get install python-tk
you can find more details here
For python2.7 try
import Tkinter
With a capital T. It should already be pre-installed in default centos 7 python setup, if not do yum install tkinter
I am running Ubuntu 16 and have both python 2 and 3. I have downloaded wxpython and it works with the python2 interpreter but not 3. I get
Python 2.7.12 (default, Nov 19 2016, 06:48:10)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import wx
>>>
and
Python 3.5.2 (default, Sep 14 2017, 22:51:06)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import wx
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named 'wx'
What do I need to do to get installed for python 3?
A similar situation arises on Fedora 25, on which I was able to solve this. Your mileage may vary on Ubuntu.
First note that wxPython is available in two major versions, let's call them wx3 and wx4. You can identify your running version through import wx; print(wx.version()). The version string on Fedora 25 reads '3.0.2.0 gtk3 (classic)', i.e. a brand of wx3. On sourceforge these versions are known as 'wxPython' and 'wxPython4', and wxpython.org calls wx4 'phoenix'.
Inspecting the source code of wx3 you will note that wx3's syntax is incompatible with python3. Conversely, wx4 is compatible both with python2.7 and python3.
wx4 doesn't seem to be available on Fedora 25, therefore python3 can't run any wx out-of-the-box. Ubuntu may or may not have the same issue.
The following worked for me to install wx4 in a python3 virtual environment:
pip install -U -f https://extras.wxpython.org/wxPython4/extras/linux/gtk3/fedora-26 wxPython
I presume the answer to your question would be
pip install -U -f https://extras.wxpython.org/wxPython4/extras/linux/gtk3/ubuntu-16.04 wxPython
In case you need to port a (py2, wx3) application to python3, you would be wise creating an intermediate step: (py2, wx3) -> (py2, wx4) -> (py3, wx4), noting that (py3, wx3) is an impossibility.
To create the (py2, wx4) environment was more cumbersome for me, because the above pip install command fails to find header files when run using pip2.
What ended up working for me was to download the 4.0.0b2 source https://pypi.python.org/packages/bc/6f/f7bb525517557e1c596bf22ef3f242b87afaeab57c9ad460cb94b3b0714e/wxPython-4.0.0b2.tar.gz#md5=2e3716205da8f52d8039095d14534bf7
and follow the build instructions https://github.com/wxWidgets/Phoenix/blob/master/README.rst , from which I only used the build command python build.py dox etg --nodoc sip build .
After building, you need to tell your python2 where to find the wx4 library. I ended up doing that by creating a virtualenv, and creating a symbolic link like so:
/home/user/venv/lib/python2.7/site-packages/wx -> /home/user/downloads/wxPython/wxPython-4.0.0b2/wx
That latter directory cointaining the result of the build.