In PHP, the function and example of isset () is explained

Source: Internet
Author: User
In PHP, the role of Isset () and its illustrative example

Check if a variable is defined


Determines whether the variable is configured.
Determine if the variable is set.
Syntax: int isset (mixed Var);
return value: Integer
Function type: PHP system functions
Content Description
This function is used to test whether a variable has been set. Returns a true value if the variable already exists. Other cases return false values.

Usage examples
$a = "Test";
echo isset ($a); True
unset ($a);
echo isset ($a); False
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