How to force packages to be installed in the correct version of Python?

Question

Python

Ubuntu. Trying to install numpy and matplotlib. I would like to have them in python3.6. At the same time, they are put in 2.7 and, of course, when you try again, a message pops up that it is already installed in 2.7.

>>sudo pip install matplotlib
Requirement already satisfied: matplotlib in /usr/lib/python2.7/dist-packages

What am I doing wrong?

Answer 1

>>sudo pip3 install matplotlib
and specifically for matplotlib, numpy and other heavy libraries with a large binary inside it is better
sudo apt-get install python3-matplotlib