is_nan math function to check if the input is number or not in PHP

echo is_nan(4); // Return  False
echo "<br>";
echo is_nan(4.78); // Return  False
echo "<br>";
echo is_nan(0); // Return  False
echo "<br>";
echo is_nan(acos(2)); // Output is True

Syntax

bool is_nan ( float $input )

Parameter	DESCRIPTION
$input	Required : Number to check.

The output is TRUE if $input is 'not a number', else False.

We can check a input or variable is a number or not by using is_nan function. Note that we can't check a string with this function.
We can check square root of a negative number with is_nan() function. Here is a sample code to check.

$v = acos(1.1);
if(is_nan($v)){
echo "this is not a number";
}else{
echo "this is a number";
}

Output is here. More about acos()

this is not a number

You can change the line $v=acos(1.1) with different values of variable $v and see the result.

$v=5.23; // this is a number

$v=4; // this is a number

Getting the output by using var_dump()

echo var_dump(is_nan(4)); // bool(false)
echo "<br>";
echo var_dump(is_nan(4.78)); // bool(false)
echo "<br>";
echo var_dump(is_nan(0)); // bool(false)
echo "<br>";
echo var_dump(is_nan(acos(2))); // bool(true)

Questions

What does the is_nan() function in PHP do?
What is the purpose of the is_nan() function in PHP?
What is the return value of the is_nan() function?
How can you use the is_nan() function to check if a variable contains a NaN (Not a Number) value?
What are some examples of values that would return true when passed to the is_nan() function?
How does the is_nan() function differ from the isNaN() function in JavaScript?
Can you use the is_nan() function to check if a string is a valid number?
How can you handle scenarios where a mathematical operation in PHP may result in a NaN value?
Are there any alternative approaches to check if a value is NaN without using the is_nan() function?
Is the is_nan() function limited to specific data types, or can it work with different types of variables?

Math Functions base_convert(): Convert number From any base to other decbin() Binary equivalent of decimal number dechex(): Convert decimal number to hexadecimal system

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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is_nan() : whether a value is not a number

Questions

Subhendu Mohapatra