I am using Sublime Text Editor for Python development. If I create a new file by Ctrl + N, the default language setting for this file is Plain Text, so how to change the default language setting for the new file to be Python ?
Another question :If I write some code in the new file and have not save it to disk, it is impossible to run it and get the running result, is there a solution to remove this restriction so that we can run code in the new file without saving it to disk first?
The second question about running without saving to hard disk:
1-press ctrl + shift + p 
2- write install package and install it
3- write "auto save" and install it
4- go to preferences> package settings> Auto-save> Settings Default and copy all the code
5- go to preferences> package settings> Auto-save> Settings user and past it and change the first code from:
"auto_save_on_modified": false,
to
"auto_save_on_modified": true,
good luck
Sublime Text: run code in a new file without saving to disk and the default language setting for a new file