Output of PHP programs | Set 2 ( Filters )

Predict the output of the following PHP programs:
Question 1

<?php
    $num = "123";
    if (!filter_var($num, FILTER_VALIDATE_INT))
        echo("Hello");
    else
        echo("Welcome to GeeksforGeeks");
?>

Options:

1. No output is returned
2. Hello
3. Welcome to GeeksforGeeks
4. Error

Output:

Welcome to GeeksforGeeks

Explanation: filter_var() – Filters a single variable with a specified filter.

Question 2

<?php
    $var=300;
    $int_options = array("options"=>array ("min_range"=>0, "max_range"=>256));
    if (!filter_var($var, FILTER_VALIDATE_INT, $int_options))
        echo("Hello");
    else
        echo("Welcome to GeeksforGeeks");
?>

Options:

1. No output is returned
2. Hello
3. Welcome to GeeksforGeeks
4. Error

Output:

Hello

Explanation: Since the integer is “300” it is not in the specified range, and the output of the code above will be: “Integer is not valid”.

Question 3

<?php
    $string = "Welcomeêê to GeêêeksfoøørGeêêeks";
    $string = filter_var($string, FILTER_SANITIZE_EMAIL);
    echo $string;
?>

Options:

1. Welcomeêê to GeêêeksfoøørGeêêeks
2. Welcomeee to GeeeeksfooorGeeeeks
3. Welcomeê to GeêeksfoørGeêeks
4. WelcometoGeeksforGeeks

Output:

WelcometoGeeksforGeeks

Explanation: Sanitize is nothing but take away invalid characters or special characters so therefore the invalid characters like ê and ø and space will be removed.

Question 4

<?php
    $value = 'GeeksforGeeks';
    $result = filter_var($value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
?>

Options:

1. FALSE
2. TRUE
3. No Output
4. ERROR

Output:

No Output

Explanation: There is an undocumented filter flag for FILTER_VALIDATE_BOOLEAN. The documentation implies that it will return NULL if the value doesn’t match the allowed true/false values. However this doesn’t happen unless you give it the FILTER_NULL_ON_FAILURE flag. Hence the output will be No Output.

Question 5

<?php
    function GeeksforGeeks($string)
    {
        return str_replace("_", " ", $string);
    }
    $string = "I_am_intern_at_GeeksforGeeks!";
    echo filter_var($string, FILTER_CALLBACK, array("options"=>"GeeksforGeeks"));
?>

Options:

1. I_am_intern_at_GeeksforGeeks!
2. IaminternatGeeksforGeeks!
3. I am intern at GeeksforGeeks!
4. Error

Output:

I am intern at GeeksforGeeks!

Explanation: The code above converts all “_” to white spaces. Call the filter_var() function with the FILTER_CALLBACK filter and an array containing our function.

Question 6

<?php
    $num = '123+abc-xyz*';
    $num = filter_var($num, FILTER_SANITIZE_NUMBER_INT);
    echo $num
?>

Options:

1. 123+abc-xyz*
2. abcxyz*
3. 123+-
4. Error

Output:

123+-

Explanation: filter_var() – with FILTER_SANITIZE_NUMBER_INT, Remove all characters except digits, +- and optionally.

Question 7

<?php
    $num = '123+-abc*';
    $res = filter_var($num, FILTER_SANITIZE_NUMBER_FLOAT);
    echo $res
?>

Options:

1. 123+abc-xyz*
2. abcxyz*
3. 123+-
4. Error

Output:

123+-

Explanation: filter_var() – with FILTER_SANITIZE_NUMBER_FLOAT, Remove all characters except digits, +- and optionally.