How to use the _ _ isset method in php
This article mainly explains "how to use the _ _ isset method in php". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let the editor take you to learn how to use the _ _ isset method in php.
Description
1. Isset () is a function used to determine whether a variable is set, pass in a variable as a parameter, and return true if the passed variable exists, otherwise return false.
2. When isset () or empty () is called on an inaccessible attribute, it will be called automatically.
Example
