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'pip3 --version' failing with a SyntaxError

This all began when I set out to install the Requests library for Python 3 (I'm running on OSX Mavericks with Python 2.7.5 (installed by brew install python) and 3.4.2 (installed by brew install python3). When I run pip3 --version (or anything related to the pip3 command) I see this:
$ pip3 --version
Traceback (most recent call last):
File "/usr/local/bin/pip3", line 7, in <module>
from pip import main
File "/usr/local/lib/python3.4/site-packages/pip/__init__.py", line 11, in <module>
from pip.vcs import git, mercurial, subversion, bazaar # noqa
File "/usr/local/lib/python3.4/site-packages/pip/vcs/mercurial.py", line 9, in <module>
from pip.download import path_to_url
File "/usr/local/lib/python3.4/site-packages/pip/download.py", line 22, in <module>
from pip._vendor import requests, six
File "/usr/local/lib/python3.4/site-packages/pip/_vendor/requests/__init__.py", line 53, in <module>
from .packages.urllib3.contrib import pyopenssl
File "/usr/local/lib/python3.4/site-packages/pip/_vendor/requests/packages/urllib3/contrib/pyopenssl.py", line 49, in <module>
from ndg.httpsclient.ssl_peer_verification import SUBJ_ALT_NAME_SUPPORT
File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/ndg/httpsclient/ssl_peer_verification.py", line 17
except ImportError, e:
^
SyntaxError: invalid syntax
When I run the Python 2.7.5 version I see this:
$ pip --version
pip 1.5.6 from /Library/Python/2.7/site-packages/pip-1.5.6-py2.7.egg (python 2.7)
Just for sanity purposes Here is what when I see when I enter the interactive interpreters:
$ python3
Python 3.4.2 (default, Oct 19 2014, 17:52:17)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.51)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()
$ python
Python 2.7.5 (default, Mar 9 2014, 22:15:05)
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()
A lot of the other answers related to updating pip3 suggest that I update pip3 with this commend pip3 install --upgrade pip which gives the same error, or I use easy_install -U pip but because of how brew sets up the Pythons, it only updates the Python 2.7.5 version (there is no easy_install3). Any ideas?

The root problem is that you somehow got a Python 2.x-only package installed into your 3.x site-packages.
Underlying that, you've actually got two different Python 2.7 installations (Apple's and Homebrew's) crossed with each other, which may have something to do with how you got a 2.7 package into 3.x as well…
Anyway, the reason this is breaking pip is that pip has various optional dependencies that it tries to import if present, and some of them do the same, and so on, and ultimately, starting up pip is importing the ndg-httpsclient package.
I'm not sure how you got that package. A standard Homebrew 3.x looks in two extra site-packages directories (fire up python3 then import sys; print(sys.path) to see all of the places it looks, both stdlib and site) beyond the one that pip3 installs into.
In this case, you've somehow installed the 2.x version of ndg-httpsclient into /usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/‌​python3.4/site-packages.
Since you didn't install it with pip—and, more to the point, since you can't run pip in the first place—you can't just pip uninstall it. So:
rm -rf /usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/‌​python3.4/site-packages/ndg*
This could break some other packages that depend on it. Once you get things working, you can use pip3 list to see all the site packages you've installed and test them out. If you want to be paranoid, do something like this:
$ pip3 list > mypackages
$ rm -rf <each site-package directory>
$ brew uninstall python3
$ brew install python3
$ pip3 install -r mypackages
You might want to similarly clean up your Homebrew 2.7 (or just scrap it and only use Apple's—especially since I'm pretty sure you're running Apple's anyway), and the site-packages for the Apple 2.7 (but not Apple's Python itself, of course, because you can't uninstall that).

Python3, lxml and "Symbol not found: _lzma_auto_decoder" on Mac OS X 10.9

I have installed python 3 using homebrew and afterwards installed pip3 and lxml.
The following line
from lxml import entree
leads to the following error:
$ python3
Python 3.3.5 (v3.3.5:62cf4e77f785, Mar 9 2014, 01:12:57)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from lxml import etree
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/3.3/lib/python3.3/site- packages/lxml/etree.so, 2): Symbol not found: _lzma_auto_decoder
Referenced from: /Library/Frameworks/Python.framework/Versions/3.3/lib/python3.3/site-packages/lxml/etree.so
Expected in: flat namespace
in /Library/Frameworks/Python.framework/Versions/3.3/lib/python3.3/site-packages/lxml/etree.so
>>> exit();
Does anybody know how to fix this?

I have deleted all versions of python from
/Library/Frameworks/Python.framework/Versions/
afterwards I have reinstalled python 3 using brew and recreated the symlinks using
brew link --overwrite python3

Deleting lxml and re-installing lxml a SECOND time worked for me (weird, not happy with this solution):
pip3.4 uninstall lxml
pip3.4 install lxml
pip3 complains about lxml being already installed, remove manually the install files with a command like:
rm -fr /private/var/folders/dj/saljfdsf12_sd7s89dfg9080000rb/T/pip_build_user/lxml
Then again:
pip3.4 install lxml
And it worked. I couldn't reproduce the original error message to find root cause of this problem.

If you use Homebrew and have xz installed, the following should work:
STATIC_DEPS=true CFLAGS=-I/usr/local/include/lzma pip install -U lxml
Otherwise set CFLAGS to the place where your lzma headers are located.

I had this same issue,
What I did:
First, I ensured I did not have the ports py27-xml2, py27-xslt or py27-lxml installed
sudo port installed | grep py27
I installed port py27-pip and checked that $PATH variable pointed it. Also installed py27-setuptools.
$ sudo port contents py27-pip | grep /pip$
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin/pip
in ~/.bash_profile:
export PATH="/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}"
$ which pip
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin/pip
Then I installed lxml with easy_install which was located in the same directory than pip
STATIC_DEPS=true sudo easy_install-2.7 lxml
The building process was displaying:
$ STATIC_DEPS=true sudo easy_install-2.7 lxml
Searching for lxml
Reading https://pypi.python.org/simple/lxml/
Downloading
....
Building without Cython.
Using build configuration of libxslt 1.1.29
Building against libxml2/libxslt in the following directory: /Applications/MAMP/Library/
....
libxml/xmlversion.h: No such file or directory
I moved MAMP (seems to already come with those libs) at the end of $PATH, uninstalled lxml (displayed "Symbol not found: _lzma_auto_decoder" error) and repeated last command:
$ STATIC_DEPS=true sudo easy_install-2.7 -m "lxml==3.6.4"
in ~/.bash_profile:
export PATH="/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}:/Applications/MAMP/Library/bin:/Applications/MAMP/Library"
$ source ~/.bash_profile
$ STATIC_DEPS=true sudo easy_install-2.7 lxml
This fixed the error either inside or outside virtualenv
$ python
Python 2.7.12 (default, Jun 29 2016, 12:46:54)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from lxml import etree
>>>

Can not import wxPython (Mac)

I thought I'd move from using Tkinter to wxPython, but I'm having some troubles. All I get is this:
>>> import wx
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named wx
I have installed wxPython. When I run the uninstaller I clearly see that wxPython IS installed:
1. wxPython3.0-osx-cocoa-py2.7 3.0.0.0
Enter the number of the install to examine or 'Q' to quit:
When I start Python I see that my version should match the version of wxPython:
Python 2.7.1 (r271:86832, Jul 31 2011, 19:30:53)
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
I'm on OS X 10.7.5 32-bit.
Any help would be awesome! :)

Macs can have multiple versions of Python installed. Are you sure that you installed wxPython for the same python you invoke with the interpreter?
Try, which python, and make sure that this version of python has a wxredirect.pth file in site-packages pointing to the wxPython installation. (If it doesn't search for wxredirect.pth.)
Here's one version on my system...
> which python2.6
/Library/Frameworks/Python.framework/Versions/2.6/bin/python2.6
> more /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/wxredirect.pth
import site; site.addsitedir('/usr/local/lib/wxPython-3.0.0.0/lib/python2.6')
#import site; site.addsitedir('/usr/local/lib/wxPython-2.9.1.1/lib/python2.6')
#import site; site.addsitedir('/usr/local/lib/wxPython-unicode-2.8.12.1/lib/python2.6')
Here, btw, I can comment out lines in the wxredirect.pth to choose the version of wxPython I want to use.

I just find the same problem.
I used brew install wxpython to install it on mac.
I try the method above but no use.
I happen to find the solution when I install another package, it showen below:
brew install tbb
Downloading https://homebrew.bintray.com/bottles/tbb-2017_U7.sierra.bottle.t
############################################################ 100.0%
==> Pouring tbb-2017_U7.sierra.bottle.tar.gz
==> Caveats
Python modules have been installed and Homebrew's site-packages is not
in your Python sys.path, so you will not be able to import the modules
this formula installed. If you plan to develop with these modules,
please run:
mkdir -p /Users/ningrongye/.local/lib/python2.7/site-packages
echo 'import site; site.addsitedir("/usr/local/lib/python2.7/site-
packages")' >> /Users/ningrongye/.local/lib/python2.7/site-
packages/homebrew.pth`
this is what homebrew said and I just try those, and it works.
ningrong

I have Python 2.7 and 3.7 .
In /usr/local/bin/ there are symbolic links for 2.7 and 3.7 Python versions and also symbolic links for pip.
I've installed wxPython with pip3
pip3 install -U wxPython
Then i checked the installation for Python3
myname$ python3
Python 3.7.2 (v3.7.2:9a3ffc0492, Dec 24 2018, 02:44:43)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import wx
>>> wx.version()
'4.0.4 osx-cocoa (phoenix) wxWidgets 3.0.5'
Antonio

In my case it worked by resetting the brew environment to 2.7:
brew link --overwrite python#2

WARNING: IPython History requires SQLite, your history will not be saved

Hi I'm using Ubuntu release 12.10 (quantal) 32-bit with Linux Kernel 3.5.0-21-generic. I'm trying to get IPython's History to work. I've set it up using pythonbrew and a virtual environment. In there I use pip to install IPython. Currently, when I start up IPython in a terminal I get:
WARNING: IPython History requires SQLite, your history will not be saved
Python 2.7.3 (default, Nov 8 2012, 18:25:10)
Type "copyright", "credits" or "license" for more information.
IPython 0.13.1 -- An enhanced Interactive Python.
? -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help -> Python's own help system.
object? -> Details about 'object', use 'object??' for extra details.
Searching on the warning in the first line, I found this issue report, so I went back and installed the following:
sudo apt-get install libsqlite0 libsqlite0-dev libsqlite3-0 libsqlite3-dev
and then removed and reinstalled pysqlite using pip
pip uninstall pysqlite
pip install pysqlite
After that I thought I would check the installation by importing the module:
Python 2.7.3 (default, Nov 8 2012, 18:25:10)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sqlite3
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/me/.pythonbrew/pythons/Python-2.7.3/lib/python2.7/sqlite3/__init__.py", line 24, in <module>
from dbapi2 import *
File "/home/me/.pythonbrew/pythons/Python-2.7.3/lib/python2.7/sqlite3/dbapi2.py", line 27, in <module>
from _sqlite3 import *
ImportError: No module named _sqlite3
So now it seems the file _sqlite3.so can't be found. That's when I found this SO question. Either it doesn't exist or it's not in my PYTHONPATH environment variable. Searching for the file, I get:
$ locate _sqlite3.so
/home/me/Desktop/.dropbox-dist/_sqlite3.so
/home/me/epd/lib/python2.7/lib-dynload/_sqlite3.so
/usr/lib/python2.7/lib-dynload/_sqlite3.so
So the file is there, but when I looked in my python path:
import sys
for p in sys.path:
print p
none of the above paths that contain _sqlite3.so were contained in my PYTHONPATH. For giggles, I added the path /usr/lib/python2.7/lib-dynload to my PYTHONPATH in a terminal and then tried to import sqlite3 again:
Python 2.7.3 (default, Nov 8 2012, 18:25:10)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path.append("/usr/lib/python2.7/lib-dynload")
>>> import sqlite3
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/me/.pythonbrew/pythons/Python-2.7.3/lib/python2.7/sqlite3/__init__.py", line 24, in <module>
from dbapi2 import *
File "/home/me/.pythonbrew/pythons/Python-2.7.3/lib/python2.7/sqlite3/dbapi2.py", line 27, in <module>
from _sqlite3 import *
ImportError: /usr/lib/python2.7/lib-dynload/_sqlite3.so: undefined symbol: PyUnicodeUCS4_DecodeUTF8
Uh oh. Now I'm completely stuck. Can anyone help me out? I've also read in a few places that I may have to rebuild Python. I have no idea how to do this in pythonbrew. Can anyone point me in the right direction?

I've also read in a few places that I may have to rebuild Python.
This is correct. SQLite is part of the standard library,
and is built when you compile Python. There are a few 'optional' parts
of the standard library, which Python will simply skip (with minimal warning, unfortunately)
if the dependencies are missing at build time, and sqlite is one of these.
You should be able to just install libsqlite3-dev,
then rebuild Python and you should be set.
Keep an eye on the build messages,
as they do report which modules they are skipping due to missing dependencies.

Thanks to minrk for pointing me in the right direction. All I had to do was rebuild python. I've outlined the steps below for those that are using pythonbrew. Notice that I already installed the libsqlite3-dev package up in the question section.
First, with the proper version of python and virtual environment loaded up run the command:
$ pip freeze -l > requirements.txt
This gives us a text file list of all of the pip packages that have been installed in the virtual environment for this particular python release in pythonbrew. Then we remove the version of python from pythonbrew and reinstall it (this is the "rebuild python" step):
$ pythonbrew uninstall 2.7.3
$ pythonbrew install 2.7.3
After that, we switch over to the newly installed python version 2.7.3 and create a new virtual environment (which I've called "sci"):
$ pythonbrew switch 2.7.3
$ pythonbrew venv create sci
$ pythonbrew venv use sci
Ideally you should be able to run the command:
$ pip install -r requirements.txt
and according to this pip should reinstall all the modules that you had in the virtual environment before we clobbered that version of python (2.7.3). It didn't work for me for whatever reason so I manually installed all of the modules using pip individuality.
$ ipython --pylab
Python 2.7.3 (default, Jan 5 2013, 18:48:27)
Type "copyright", "credits" or "license" for more information.
IPython 0.13.1 -- An enhanced Interactive Python.
? -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help -> Python's own help system.
object? -> Details about 'object', use 'object??' for extra details.
and IPython history works!

What worked for me (using osx + homebrew + brewed python):
# Reinstall Python 2.7 with sqlite
brew remove python
brew install readline sqlite gdbm --universal
brew install python --universal --framework
# Reinstall iPython with correct bindings
pip uninstall ipython
pip install ipython
And you should be good to go.

You should rebuild your python with sqlite support
sudo apt-get install libsqlite3-dev
wget https://www.python.org/ftp/python/2.7.15/Python-2.7.15.tgz
tar -xvf Python-2.7.15.tgz
cd Python-2.7.15
./configure
make
sudo make install
Recreate your virtual environment and you should be good to go
rmvirtualenv venv
mkvirtualenv -p python2 venv
workon venv
pip install -r requirements.txt
# or
pip install ipython

This warning appears on macOS when python is installed with pyenv. By default it installs python without sqlite. These commands reinstall python with sqlite support:
pyenv uninstall 3.7
CFLAGS="-I$(xcrun --show-sdk-path)/usr/include" pyenv install 3.7

Python 2.7 cannot import PyQt4

I've upgraded to Python 2.7 from Python 2.6 on Ubuntu Maverick Meerkat (10.10) and I'm unable to import PyQt4.
austin#gerald:~$ python2.7
Python 2.7.0+ (r27:82500, Sep 15 2010, 18:04:55)
[GCC 4.4.5] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import PyQt4
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named PyQt4
I installed both Python 2.7 (python2.7) and PyQt4 (python-qt4) from the Ubuntu repositories. I installed PyQt a while back, but I installed Python 2.7 recently.
If I try Python 2.6 (since it's shipped with Ubuntu, the command is simply python), it works perfectly. Watch:
austin#gerald:~$ python
Python 2.6.6 (r266:84292, Sep 15 2010, 15:52:39)
[GCC 4.4.5] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import PyQt4
I know what the problem is: the PyQt4 modules are accessible by Python 2.6 but not 2.7. My question is, how do I get Python 2.7 to find the PyQt4 module(s)? Help!
Note: sorry if this belongs in Super User, I was just programming when I encountered this problem.

As PyQt is not using setup.py it cannot be installed using pip or easy_install
Here you have a tutorial showing how to build and install PyQt for python2.7:
http://problemssol.blogspot.com/2010/12/compile-and-install-pyqt4-for-python27.html
Update:
For Ubuntu 12.04+ just use apt-get:
apt-get install python-qt4

Under Ubuntu system, you could install it via apt-get
apt-get install python-qt4

OSX 10.8.2 tested:
sudo pip install SIP
got IOError: [Errno 2] No such file or directory: '/tmp/pip-build/SIP/setup.py'
It's ok then:
cd /tmp/pip-build/SIP
sudo python configure.py
make
sudo make install
download PyQt from: http://sourceforge.net/projects/pyqt/files/PyQt4/PyQt-4.9.6/PyQt-mac-gpl-4.9.6.tar.gz
unzip it.
cd PyQt-mac-gpl-4.9.6
sudo python configure.py
make
it will take a while, after make then:
sudo make install
Enjoy it :)

You can download any version of PyQt4 here for any version of Python but since you asked for python 2.7, Here is the link for the download for python 2.7:
https://sourceforge.net/projects/pyqt/files/PyQt4/PyQt-4.11.4/

You should install PyQt4 in the Python 2.7 environment. To do this run
easy_install2.7 PyQt4
If easy_install is not installed you will need to first download and install it by running
python2.7 setup.py install

Please install SIP module first,this is python and c/c++ lib tools, and PyQt4 lib