title: How to fix python3 instalation on linux mint
body: <p>So I've been using linux mint mate for a while, and everything was working fine. 
  So as I got a new notebook, I installed the new version of linux mint (19.2 - Tina) alongside the windows 10. Everything went right, I think. </p>
  
  <p>Now, I'm trying to get it ready for use, and it's not working. </p>
  
  <p>It supposedly came with both versions of python:</p>
  
  <ul>
  <li>Python 2.7.15+</li>
  <li>Python 3.6.8</li>
  </ul>
  
  <p>But when I tried to run a simple hello world, but importing the essentials packages for me, something like this</p>
  
  <pre><code>import numpy as np
  import math #as ma
  import matplotlib.pyplot as plt; plt.switch_backend('agg')
  import sys
  import pandas as pd
  import seaborn as sns; sns.set()
  import powerlaw as pl
  from itertools import zip_longest
  import csv
  import os
  
  print('hello world')
  </code></pre>
  
  <p>It didn't even recognize the numpy package, and I got the following:</p>
  
  <pre><code>Traceback (most recent call last):
    File "testes.py", line 1, in &lt;module&gt;
      import numpy as np
  ModuleNotFoundError: No module named 'numpy'
  </code></pre>
  
  <p>So I went to this website and tried following the tutorial </p>
  
  <p><a href="https://packaging.python.org/tutorials/installing-packages/#id18" rel="nofollow noreferrer">https://packaging.python.org/tutorials/installing-packages/#id18</a></p>
  
  <p>But when I tried to install numpy the result was as bellow:</p>
  
  <pre><code>(tutorial_env) jheniffer@jheniffer-5480:~/Dropbox/teste_cros_bi$ pip install python3-numpy
  Collecting python3-numpy
  Exception:
  Traceback (most recent call last):
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/basecommand.py", line 215, in main
      status = self.run(options, args)
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/commands/install.py", line 353, in run
      wb.build(autobuilding=True)
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/wheel.py", line 749, in build
      self.requirement_set.prepare_files(self.finder)
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/req/req_set.py", line 380, in prepare_files
      ignore_dependencies=self.ignore_dependencies))
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/req/req_set.py", line 554, in _prepare_file
      require_hashes
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/req/req_install.py", line 278, in populate_link
      self.link = finder.find_requirement(self, upgrade)
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/index.py", line 465, in find_requirement
      all_candidates = self.find_all_candidates(req.name)
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/index.py", line 423, in find_all_candidates
      for page in self._get_pages(url_locations, project_name):
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/index.py", line 568, in _get_pages
      page = self._get_page(location)
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/index.py", line 683, in _get_page
      return HTMLPage.get_page(link, session=self.session)
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/lib/python3.6/site-packages/pip/index.py", line 795, in get_page
      resp.raise_for_status()
    File "/home/jheniffer/Dropbox/teste_cros_bi/tutorial_env/share/python-wheels/requests-2.18.4-py2.py3-none-any.whl/requests/models.py", line 935, in raise_for_status
      raise HTTPError(http_error_msg, response=self)
  requests.exceptions.HTTPError: 404 Client Error: Not Found for url: https://pypi.org/simple/python3-numpy/
  </code></pre>
  
  <p>I don't know what should I do to get this running, 
  how should I proceed to install everything, because I thought that the basic packages, like numpy for example, was already installed, and every other time that I tried installing something by pip (on my previous laptop) it worked with just</p>
  
  <p><code>pip3 install python3-numpy</code></p>
  
  <p>I tried the option without pip, it installed successfully</p>
  
  <pre><code>(tutorial_env) jheniffer@jheniffer-5480:~/Dropbox/teste_cros_bi$ sudo apt install python3-numpy
  [sudo] password for jheniffer:             
  Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  Suggested packages:
    gfortran python-numpy-doc python3-dev python3-nose python3-numpy-dbg
  The following NEW packages will be installed:
    python3-numpy
  0 upgraded, 1 newly installed, 0 to remove and 287 not upgraded.
  Need to get 1.943 kB of archives.
  After this operation, 10,9 MB of additional disk space will be used.
  Get:1 http://archive.ubuntu.com/ubuntu bionic/main amd64 python3-numpy amd64 1:1.13.3-2ubuntu1 [1.943 kB]
  Fetched 1.943 kB in 4s (528 kB/s)          
  Selecting previously unselected package python3-numpy.
  (Reading database ... 308507 files and directories currently installed.)
  Preparing to unpack .../python3-numpy_1%3a1.13.3-2ubuntu1_amd64.deb ...
  Unpacking python3-numpy (1:1.13.3-2ubuntu1) ...
  Setting up python3-numpy (1:1.13.3-2ubuntu1) ...
  Processing triggers for man-db (2.8.3-2ubuntu0.1) ...
  </code></pre>
  
  <p>But when I tried to run the hello word code, I got this message again</p>
  
  <pre><code>(tutorial_env) jheniffer@jheniffer-5480:~/Dropbox/teste_cros_bi$ python3 testes.py 
  Traceback (most recent call last):
    File "testes.py", line 1, in &lt;module&gt;
      import numpy as np
  ModuleNotFoundError: No module named 'numpy'
  
  
  </code></pre>