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

In PHP, the role of Isset () and its illustrative example
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Check if a variable is defined

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Determines whether the variable is configured.
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Isset
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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