Conversion of data types

Data type conversions

By default only data that matches the operator can be calculated directly

For example: +???????? You can only operate on numeric type data directly,

When the data type does not match the operator, PHP automatically converts it.

(int)???????? Casting other data types to integers

Example:

(string)???????? Casting other data types to strings

Example:

(Boolean)???? Casting other data types to Boolean

Example:

?

Empty ();???? Determining whether a variable is empty and the value of a variable can be converted to Boolean false is considered null.

Null, value 0, character spaces, false, empty array, undefined variable

Example:

Conversion of data types