ubuntu18.04にpipをインストール

Question

ubuntu18.04にpipをインストールしてpipenvをインストールしたいのですがどちらの方法がよいのでしょうか？

1の場合だとaptでインストールした後pipenvのあとpip3のpathが変わっています。
aptでインストールしたのを消すべき？

2の場合だと"/home/barobaro/.local/bin"をPATHに追加しなさいと警告がでます。
pip3ではなくpipなのも気になります。

どちらよいのでしょうか？

1. python3-pip

sudo apt install python3-pip

pip 9.0.1 from /usr/lib/python3/dist-packages (python 3.6)

pip3 install pipenv --user

pip3 --version

Traceback (most recent call last):
  File "/usr/bin/pip3", line 9, in <module>
    from pip import main

source ~/.profile

pip3 --version
pip 18.1 from /home/barobaro/.local/lib/python3.6/site-packages/pip (python 3.6)

2. get-pip.py

sudo apt install python3-distutils
wget https://bootstrap.pypa.io/get-pip.py
sudo -H python3 get-pip.py

pip --version
pip 18.1 from /usr/local/lib/python3.6/dist-packages/pip (python 3.6)

pip install pipenv --user

  The script virtualenv is installed in '/home/barobaro/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
  The script virtualenv-clone is installed in '/home/barobaro/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
  The scripts pipenv and pipenv-resolver are installed in '/home/barobaro/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.

参考リンク
https://www.python.jp/install/ubuntu/index.html
http://icchy.hatenablog.jp/entry/2018/04/17/064443
https://qiita.com/koshian2/items/9763be71c1b3db209288