Where can I get good other people's codes to parse for learning purposes?

Question

PHP

Hello! Actually, everything is in the title...
According to general advice, in order to learn the correct coding, you need to watch someone else's CORRECT codes somewhere. But where to get exactly the right ones, or more similar to this concept?

Answer 1

You can take a repository of a large framework and study (for example: symfony, yii, etc.)

Answer 2

Here are two codes:
Which one is correct?