Hello @Ntg, welcome to the forums .
Well you got the demo working, which is great ! Now for your case, if you are running
streamlit run app.py, Streamlit will you look for a file
app.py in the folder the terminal is running in, and from the error
File does not exist: app.py it seems it could not find the file.
Don’t forget to create such a file in the folder where your terminal is running . On Windows the folder you are in should be written the line before, on Unix, you can type
pwd to see the folder it’s in.
If you managed to create your script
app.py, you should see the file in the terminal using the
dir command in Windows/
ls command in Unix in the list of files in your terminal.
Then for example you can write the following code in the
app.py file, using Notepad++ or Notepad :
import streamlit as st
st.header("Hello world !")
and hopefully Streamlit will pop out and cheer you with balloons when you run the command.
We can help you a bit more if you specify on which OS you are running, if you are using Anaconda Navigator to manage your packages, and how you installed Streamlit, so don’t hesitate to provide us more information about your setup.