python - 如何让我的电脑知道我现在想使用 python 3？

Question

我安装了 mac 和 python 2.something。我最近安装了 python3 和 pip3。然后我尝试运行以下命令:

pip3 install django==2.2

django-admin startproject myProject

cd myProject

一切正常，但是当我运行时

python3 manage.py runserver

它提示

Traceback (most recent call last):
  File "manage.py", line 10, in main
    from django.core.management import execute_from_command_line
ModuleNotFoundError: No module named 'django'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "manage.py", line 21, in <module>
    main()
  File "manage.py", line 16, in main
    ) from exc
ImportError: Couldn't import Django. Are you sure it's installed and available on your PYTHONPATH environment variable? Did you forget to activate a virtual environment?

我的电脑还在用旧版本思考吗？我对“环境变量”不熟悉，需要修改吗？ (我问是因为我还读到修改那些东西可能是不安全的)

另外，当我运行时

python --version

它给了我 2.7

但是我仍然可以使用“python3”命令运行 .py 文件

Answer 1

首先尝试使用 python3 -m pip install django

然后运行命令python3 manage.py runserver

看起来你正在 Python 2 上安装 django