Is there an equivalent for toPrecision() in PHP? - php

Question

For example a number to 3 significant figures would be as follows
12345 => 12300
0.12345 => 0.123
0.012345 => 0.0123

Answer 1

There's nothing built in to round to a given number of significant figures (as opposed to a given number of digits.) Math to the rescue!
function toPrecision($number, $precision) {
if ($number == 0) return 0;
$exponent = floor(log10(abs($number)) + 1);
$significand =
round(
($number / pow(10, $exponent))
* pow(10, $precision)
)
/ pow(10, $precision);
return $significand * pow(10, $exponent);
}
$numbers = [
12345,
.12345,
.012345,
];
foreach($numbers as $number) {
echo toPrecision($number, 3), "\n";
}
Output:
12300
0.123
0.0123

Answer 2

In php, you could use round() function. It accepts two parameters, the number and precision, such as
echo round(12345, -2); # will result in 12300
echo round(0.12345, 3); # will result in 0.123
See the php manual on round() for more information.

Answer 3

There are several functions you can use for math operations. Here are a few examples
// 0.12345 => 0.123 - round half down
$result = round(0.12345, 3, PHP_ROUND_HALF_DOWN)
// 0.12345 => 0.124 - natural rounding
$result = round(0.12345. 3);
// 12345 => 12300
$result = round(12345, -2, PHP_ROUND_HALF_DOWN);
The round() function rounds integers by the given precision. Please respect the natural sorting. Higher than 5 means rounding up as far as you don 't mention the PHP_ROUND_HALF_DOWN constant.

Answer 4

You can use number_format() to achieve what you need.
$value = 0.12345;
$output = number_format($value, 3);
echo $output;
This will return: 0.123
Or you could wrap this withing a foreach loop if you need to go through an array, or alternatively create your own function to accept an integer and return the formatted value.
function formatNumber($int){
$number = number_format($int, 3);
return $number;
}
Or alternatively look at the link below to see if there is any other way you want to do this.
PHP.NET PAGE