在python3中，安装twis​​ted后，当导入twisted时，它显示“ ImportError：没有名为“ twisted”的模块”

Question

I install the ubuntu 14.04LTS as a virtual machine, it has already install the python2.7 et python3.4 in the machine. After that I use the command sudo apt-get install python-twisted to install the framework twisted, I can use import twisted in python 2.7 but I can't use this same command import twisted in python 3.4. It shows

>>> import twisted
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named 'twisted'

I have try many way to install the twisted, like

sudo apt-get install python-setuptools
Sudo apt-get install python-dev
Sudo easy_install twisted

or

sudo pip install twisted

even download the pack tar xjf Twisted-13.1.0.tar.bz2 and tar xzf zope.interface-3.6.1.tar.gz than run python setup.py install

However,unfortunately, these don't work. Does anybody knows how to solute this problem? Thanks !

Answer 1

This is because all of these libraries are installing to Python 2.7's libraries.

To install to Python 3, use pip3 , not pip :

sudo pip3 install twisted

---

To understand why this happened to you, note that Ubuntu symlinks python to the python2.7 executable and python3 to python3.4 .

From what I understand, packages such as these on apt-get internally call python during installation rather than python3 . Hence why nothing gets installed to Python 3.4 in those cases.

The safe alternative is always to use pip for Python installation. pip3 is symlinked to the version of pip that services only Python 3.4, so always call that for Python 3 packages.

An even better solution is to use virtualenv to isolate different Python and pip versions from each other. That way, when you enter a virtual environment, you can use pip without worrying about the symlinked version.