In PHP isset Method is Used For Checking if Variable is Defined

In PHP, the isset() method is used for checking if one or more variables have been declared and are not null.

$variable = "I'm a variable";

if (isset($variable)) {
    echo "variable has been declared!";
} else {
   echo "variable hasn't been declared!"
}

if (isset($variable, $another_variable)) {
    echo "all variables have been declared!";
} else {
   echo "all variables haven't been declared!"
}

//Output:
variable has been declared!
all variables haven't been declared!

In php, the isset() method is used for checking if variables have been defined or not.

The isset() function in php takes one or more variables and checks to see if each variable is declared and is different than null.

isset() returns true if the variable exists and false if the variable hasn’t been declared or is null.

If multiple variables are provided, isset() returns true only when all variables passed have been declared.

Below are some examples of using isset() in php to check if one or more variables have been declared.

$variable = "I'm a variable";

if (isset($variable)) {
    echo "variable has been declared!";
} else {
   echo "variable hasn't been declared!"
}

if (isset($variable, $another_variable)) {
    echo "all variables have been declared!";
} else {
   echo "all variables haven't been declared!"
}

$another_variable = "Another variable";

if (isset($variable, $another_variable)) {
    echo "all variables have been declared!";
} else {
   echo "all variables haven't been declared!"
}

//Output:
variable has been declared!
all variables haven't been declared!
all variables have been declared!

Hopefully this article has been useful for you to learn that in PHP, the isset() method allows you to check if variables have been declared.