Create an environment
Create a project folder and a venv folder within:
$ mkdir myproject
$ cd myproject
$ python3 -m venv venv
On Windows:
$ py -3 -m venv venv
If you needed to install virtualenv because you are using Python 2, use the following command instead:
$ python2 -m virtualenv venv
On Windows:
> \Python27\Scripts\virtualenv.exe venv
Activate the environment
Before you work on your project, activate the corresponding environment:
$ . venv/bin/activate
On Windows:
> venv\Scripts\activate
Your shell prompt will change to show the name of the activated environment.
Install Flask
Within the activated environment, use the following command to install Flask:
$ pip install Flask
Flask is now installed. Check out the
Quickstart or go to the
Documentation Overview.
Living on the edge
If you want to work with the latest Flask code before it’s released, install or update the code from the master branch:
$ pip install -U
https://github.com/pallets/flask/archive/master.tar.gz
Install virtualenv
If you are using Python 2, the venv module is not available. Instead, install
virtualenv.
On Linux, virtualenv is provided by your package manager:
# Debian, Ubuntu
$ sudo apt-get install python-virtualenv
# CentOS, Fedora
$ sudo yum install python-virtualenv
# Arch
$ sudo pacman -S python-virtualenv
If you are on Mac OS X or Windows, download
get-pip.py, then:
$ sudo python2 Downloads/get-pip.py
$ sudo python2 -m pip install virtualenv
On Windows, as an administrator:
> \Python27\python.exe Downloads\get-pip.py
> \Python27\python.exe -m pip install virtualenv
Now you can return above and
Create an environment.
flask.palletsprojects.com
Cũng là may có các cậu em, các cậu í bảo, hệ điều hành cũng dùng python có sẵn trong máy, nên anh phải thiết lập môi trường ảo cho nó 
hoặc bác log lại, hoặc bác pop cái thông báo vào mặt user chứ.
