Python 正在尝试安装并运行Flask，但我一直收到错误消息

我感谢任何愿意帮助我解决这个问题的人。我目前正在学习一门机器学习课程，但我在试图找出什么应该是简单的安装时已经失败了。我会尽力解释，但请耐心，因为我是新手

我正在使用Terminal运行一个非常基本的Flask应用程序。在终端我可以安装烧瓶。我在终端中键入了以下两个命令：

导出FLASK_APP=hello.py

烧瓶运行

运行flask后，我现在收到一条错误消息，阻止我继续： 错误：无法导入“hello”

上面是我在Sublime中使用的代码，应该允许返回“Hello，World！"

该命令应该在URL地址上运行，但它只是告诉我它不会导入“hello”。hello.py是包含代码的Sublime保存文件

如果这听起来令人困惑，我很抱歉，因为我完全困惑了，甚至不知道如何正确地表达我的问题。如果有人能帮助我，我会尽力提供尽可能多的信息，但如果有人熟悉的话，我正在学习的机器学习课程是Siraj Raval课程。这确实是介绍中的第二个视频你可以想象，我感到非常沮丧，因为我在试图理解这一点时已经遇到了严重的问题。谢谢你的阅读，非常感谢你的帮助

如果这有帮助，下面是我使用的命令提示的确切顺序>>

Last login: Sun Sep 22 17:25:19 on ttys000
Justins-MacBook-Pro:~ justinunion$ mkdir myproject
mkdir: myproject: File exists
Justins-MacBook-Pro:~ justinunion$ cd myproject/
Justins-MacBook-Pro:myproject justinunion$ python3 -m venv venv
Justins-MacBook-Pro:myproject justinunion$ . venv/bin/activate
(venv) Justins-MacBook-Pro:myproject justinunion$ pip3 install flask
Requirement already satisfied: flask in ./venv/lib/python3.7/site-packages (1.1.1)
Requirement already satisfied: click>=5.1 in ./venv/lib/python3.7/site-packages (from flask) (7.0)
Requirement already satisfied: itsdangerous>=0.24 in ./venv/lib/python3.7/site-packages (from flask) (1.1.0)
Requirement already satisfied: Werkzeug>=0.15 in ./venv/lib/python3.7/site-packages (from flask) (0.16.0)
Requirement already satisfied: Jinja2>=2.10.1 in ./venv/lib/python3.7/site-packages (from flask) (2.10.1)
Requirement already satisfied: MarkupSafe>=0.23 in ./venv/lib/python3.7/site-packages (from Jinja2>=2.10.1->flask) (1.1.1)
(venv) Justins-MacBook-Pro:myproject justinunion$ sublime
-bash: sublime: command not found
(venv) Justins-MacBook-Pro:myproject justinunion$ ls
venv
(venv) Justins-MacBook-Pro:myproject justinunion$ sublime hello.py
-bash: sublime: command not found
(venv) Justins-MacBook-Pro:myproject justinunion$ ls
venv
(venv) Justins-MacBook-Pro:myproject justinunion$ export FLASK_APP=hello.py
(venv) Justins-MacBook-Pro:myproject justinunion$ flask run
 * Serving Flask app "hello.py"
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
Usage: flask run [OPTIONS]

Error: Could not import "hello".
(venv) Justins-MacBook-Pro:myproject justinunion$ 

---

什么目录是

hello.py

中，当您键入

flask run

时您在什么目录中，以及您的

PYTHONPATH

是什么？显示

树的输出

命令，让我们了解正在发生的事情。感谢您的回复，并感谢您的耐心。我对此非常陌生，所以我不确定我在哪个目录中或者PYTHONPATH是什么。我正在使用Python 3，我已经编辑了我的帖子，以包含所使用的命令行。我希望这会有所帮助。您必须与

hello.py

位于同一目录中，否则Python将找不到它。PYTHONPATH是一个环境变量，其中包含Python将搜索的路径列表modules@Justin开学最后，键入

ls

并查看文件夹的内容，应该有一个hello.py文件。如果没有，请复制hello.py文件并将其存储在当前工作目录中，可以使用命令

pwd

Last login: Sun Sep 22 17:25:19 on ttys000
Justins-MacBook-Pro:~ justinunion$ mkdir myproject
mkdir: myproject: File exists
Justins-MacBook-Pro:~ justinunion$ cd myproject/
Justins-MacBook-Pro:myproject justinunion$ python3 -m venv venv
Justins-MacBook-Pro:myproject justinunion$ . venv/bin/activate
(venv) Justins-MacBook-Pro:myproject justinunion$ pip3 install flask
Requirement already satisfied: flask in ./venv/lib/python3.7/site-packages (1.1.1)
Requirement already satisfied: click>=5.1 in ./venv/lib/python3.7/site-packages (from flask) (7.0)
Requirement already satisfied: itsdangerous>=0.24 in ./venv/lib/python3.7/site-packages (from flask) (1.1.0)
Requirement already satisfied: Werkzeug>=0.15 in ./venv/lib/python3.7/site-packages (from flask) (0.16.0)
Requirement already satisfied: Jinja2>=2.10.1 in ./venv/lib/python3.7/site-packages (from flask) (2.10.1)
Requirement already satisfied: MarkupSafe>=0.23 in ./venv/lib/python3.7/site-packages (from Jinja2>=2.10.1->flask) (1.1.1)
(venv) Justins-MacBook-Pro:myproject justinunion$ sublime
-bash: sublime: command not found
(venv) Justins-MacBook-Pro:myproject justinunion$ ls
venv
(venv) Justins-MacBook-Pro:myproject justinunion$ sublime hello.py
-bash: sublime: command not found
(venv) Justins-MacBook-Pro:myproject justinunion$ ls
venv
(venv) Justins-MacBook-Pro:myproject justinunion$ export FLASK_APP=hello.py
(venv) Justins-MacBook-Pro:myproject justinunion$ flask run
 * Serving Flask app "hello.py"
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
Usage: flask run [OPTIONS]

Error: Could not import "hello".
(venv) Justins-MacBook-Pro:myproject justinunion$