from python3 dockerfile code example

Example 1: install python3 in dockerfile

RUN apk upgrade --update && apk add --no-cache python3 python3-dev

Example 2: install python in dockerfile

RUN apt-get update
RUN apt-get install python

Example 3: install python 3.6 dockerfile

RUN apt-get install -y build-essential python3.6 python3-pip python3.6-venv