Arrays are a very important data type in PHP.

Because it involves too many knowledge points and is too complicated, our explanation is to give you an overview in the array type part, and then use a dedicated chapter to explain it to you.

When learning arrays, we mainly learn two parts of knowledge:

1. The definition of arrays, some pitfalls to pay attention to in the definitions
2. The function usage of arrays and ( Silent writing)

It is also the silent writing level