python3.7 的 pip (Ubuntu 16.04)

Question

I am not able to install pip for python 3.7. When I tried to search online, one solution I found was to install pip using get-pip.py. However, it's failing for me:

sudo python3.7 get-pip.py
Traceback (most recent call last):
  File "get-pip.py", line 21373, in <module>
    main()
  File "get-pip.py", line 197, in main
    bootstrap(tmpdir=tmpdir)
  File "get-pip.py", line 82, in bootstrap
    import pip._internal
  File "/tmp/tmp3273u8va/pip.zip/pip/_internal/__init__.py", line 40, in <module>
  File "/tmp/tmp3273u8va/pip.zip/pip/_internal/cli/autocompletion.py", line 8, in <module>
  File "/tmp/tmp3273u8va/pip.zip/pip/_internal/cli/main_parser.py", line 12, in <module>
  File "/tmp/tmp3273u8va/pip.zip/pip/_internal/commands/__init__.py", line 6, in <module>
  File "/tmp/tmp3273u8va/pip.zip/pip/_internal/commands/completion.py", line 6, in <module>
  File "/tmp/tmp3273u8va/pip.zip/pip/_internal/cli/base_command.py", line 19, in <module>
  File "/tmp/tmp3273u8va/pip.zip/pip/_internal/download.py", line 37, in <module>
  File "/tmp/tmp3273u8va/pip.zip/pip/_internal/utils/glibc.py", line 3, 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'

Now, to resolve this, I found that libffi-dev package should be installed. However, I verified that this package is already installed on my system. I am not sure how should I resolve this. Can someone please help?

sudo apt-get install libffi-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
libffi-dev is already the newest version (3.2.1-4).
0 upgraded, 0 newly installed, 0 to remove and 50 not upgraded.

Update: I followed the steps to install Python 3.7 from https://serverfault.com/questions/918335/best-way-to-run-python-3-7-on-ubuntu-16-04-which-comes-with-python-3-5 . Also, When I check for pip3.7 installation, I am getting the output as

$ pip3.7 --version
pip 19.0.1 from /usr/local/lib/python3.5/dist-packages/pip (python 3.5)
$ sudo apt install python3-pip
Reading package lists... Done
Building dependency tree       
Reading state information... Done
python3-pip is already the newest version (8.1.1-2ubuntu0.4).
0 upgraded, 0 newly installed, 0 to remove and 50 not upgraded.

But when I execute my program, I get an error like /usr/local/bin/python3.7: No module named pip .

Answer 1

Actually it's a lot simpler. Assuming your Linux is Debian-based (for exaxample, Ubuntu), you should install pip with sudo apt install python3-pip for Python 3.x as you wish, or with sudo apt install python-pip for Python 2.x.

If your OS is not debian based, just change the package manager in use (for example use yum or pacman instead of apt).

Here , you can also find a guide for installing pip on Ubuntu 18.04.

Hope this helps!

Answer 2

I installed python3.7 in Ubuntu 16.04 via ppa ( sudo add-apt-repository ppa:deadsnakes/ppa ) (See detailed instructions ppa installation Python3.7 )

For me, Nick Tritsis answer did not work. The only way to install pip was directly downloading the file get-pip.py and running it on python 3.7 (according to the method in the official site )

python3.7 get-pip.py

However, as I did so I got an error message

ERROR: Could not install packages due to an 
EnvironmentError: [Errno 13] Permission denied:

One not recommended solution is to use sudo :

sudo python3.7 get-pip.py

Recommended Solution

One can just supply the argument --user when calling the script like so:

  python3.7 get-pip.py --user

credits to @Matthew Strasiotto, who suggested me this solution.

Alternative Solution

This alternative solution is for fun; it is more complicated than the recommended: We can add the option --user into the file.

So we open the file get-pip.py and we change the code line where the command arguments are given: we added there the argument --user that makes installation possible.

Original line:

# Add our default arguments
 args = ["install", "--upgrade", "--force-reinstall"] + args

Modified line:

# Add our default arguments
args = ["install", "--user", "--upgrade", "--force-reinstall"] + args

After this modification python3.7 get-pip.py runs smooth.