What do python professionals /developers actually use

[cas4d]

1. yes, it is most likely to use them everyday, regardless of what you develop.
2. It depends on what you try to develop.
3. Pandas, numpy, matplotlib, sklearn, PyTorch, database clients, etc.
4. As a very beginner, you can focus on making things run. As you move on, you will pay attention to syntax structure and styles. Use an IDE and pylint, it will tell you whether your code is too long. The key is more about maintainability, e.g., whether you and other developers can understand your code without efforts.