How to delete variables and detect variables in PHP

This article mainly shares with you the methods of deleting variables and detecting variables in PHP. I hope it can help you.

1. Delete variables:

Syntax:

unset($variable name);

2. Detect variables

Syntax: isset($variable name); detects whether the variable exists, only true and false, the browser displays 0 or 1.

When you want to display true or false, use var_dump(isset($variable name) ) to make a judgment.

var_dump() output content length, type, value, mainly used for program debugging

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