Common ways to solve zero-dividing errors with is_finite

gitbox 2025-05-26

In PHP, the zero division error is a common runtime error, especially when performing mathematical operations, if the denominator is zero, it will cause the program to throw a warning or an exception. To avoid this, we usually need to check the value of the divisor in advance to make sure it is a valid number and is not zero. PHP provides the is_finite() function to determine whether a value is a finite value, which is very helpful for catching the zero division error.

What is the is_finite function?

is_finite() is a function in PHP to detect whether a numeric value is a finite value. Return true if the argument is a finite number (neither infinity nor non-number NaN), otherwise return false .

 <?php
var_dump(is_finite(10));    // bool(true)
var_dump(is_finite(INF));   // bool(false)
var_dump(is_finite(NAN));   // bool(false)
?>

Ideas to avoid zero-removal errors using is_finite

When performing division operations, we can first determine whether the denominator is zero or non-finite number. If it is not a finite number, avoid division, or give default values or error prompts.

Sample code

 <?php
function safe_divide($numerator, $denominator) {
    // Determine whether the denominator is finite and not zero
    if (is_finite($denominator) && $denominator != 0) {
        return $numerator / $denominator;
    } else {
        return "mistake：The denominator cannot be zero or invalid";
    }
}

// test
echo safe_divide(10, 2);   // Output 5
echo safe_divide(10, 0);   // Output mistake：The denominator cannot be zero or invalid
echo safe_divide(10, INF); // Output mistake：The denominator cannot be zero or invalid
?>

In this example, is_finite() determines whether the denominator is a finite number, and can effectively avoid the zero-dividing error with the $denominator != 0 condition.

Other common ways to avoid zero-deletion errors

Directly determine whether it is zero

 if ($denominator == 0) {
    // 处理mistake
} else {
    $result = $numerator / $denominator;
}

Use ternary operator to assign default values

 $result = ($denominator == 0) ? 0 : $numerator / $denominator;

Utilize exception handling

For PHP 7 and above, you can handle DivisionByZeroError exception thrown by catching the zero-dividing:

 try {
    $result = $numerator / $denominator;
} catch (DivisionByZeroError $e) {
    echo "除零mistake：" . $e->getMessage();
}

Combined with is_finite function

As shown above, combined with is_finite(), it can detect the validity of the divisor, avoiding the case where the denominator is infinity or NaN.

Summarize

The is_finite() function is a good tool in PHP to judge the validity of numeric values. Combined with zero-dividing judgment, it can help developers write more robust code to avoid zero-dividing errors causing program crashes. In addition, rational use of conditional judgment and exception handling is also a common and effective way. According to actual needs, choosing the right error protection method can improve the security and stability of the code.

is_finite