Why Does PHP Output My Floating-Point Number in Scientific Notation, and How Can I Fix It?

PHP Outputting Number in Scientific Notation

In PHP, when dealing with floating-point numbers, certain values may be displayed in scientific notation, even when a specific decimal format is specified. This can be encountered when assigning a value to a variable, as in the example below:

$var = .000021;
echo $var;

Instead of the expected ".000021," the output is "2.1E-5." This is because PHP employs a default precision for floating-point numbers, which can lead to rounding errors.

To resolve this issue and ensure that the number is printed in the desired format, use the number_format() function:

print number_format($var, 5);

This function takes the original number and the desired number of decimal places as arguments. By specifying "5" as the second argument, we ensure that the number will be formatted with five decimal places, resulting in ".000021."

Alternatively, you can use the sprintf() function to achieve the same result:

print sprintf("%.5f", $var);

By using these functions, you can explicitly control the formatting of floating-point numbers and prevent them from being displayed in scientific notation.

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