What's a correct way to round (or cut) a PHP float after 3 characters, not counting 0's?
Example:
0.12345 => 0.123
0.012345 => 0.0123
0.0001239 => 0.000124
You can use regex to capture the zeros and dots separated from digits and handle them separately.
$arr = [0.12345,0.012345,0.0001239];
Foreach($arr as $val){
Preg_match("/([0\.]+)([0-9]+)/", $val, $match);
Echo $match[1]. Substr(round("0.".$match[2],3),2,3)."
";
}
The regex works by first capture group is grabbing 0 and dots greedy, so any dots or zeros in sequence is captured.
Then the second group captures 0-9, but since the first group is greedy this can't start with 0.
So second group has to start with 1-9 then any 0-9 digits.
You can do this using number_format() and first write function which counts zeroes after point:
function countPrecision($n){
$p = 0;
$n = substr($n, 2);
foreach(str_split($n) as $i)
{
if($i == '0')
$p += 1;
else
break;
}
return $p;
}
$n = 0.12345; //your number
$p = countPrecision($n) + 3
echo number_format((float) $n, $p, '.', '');
You would need something custom to detect the number of zeros made of this PHP - Find the number of zeros in a decimal number and round http://php.net/manual/en/function.round.php
$num1 = 0.12345;
$num2 = 0.012345;
$num3 = 0.0001239;
echo "<br/><br/> Three zero places rounding number 1 : " . threeZeroPlaceRounding($num1);
echo "<br/><br/> Three zero places rounding number 2 : " . threeZeroPlaceRounding($num2);
echo "<br/><br/> Three zero places rounding number 3 : " . threeZeroPlaceRounding($num3);
function threeZeroPlaceRounding($number)
{
$numzeros = strspn($number, "0", strpos($number, ".")+1);
$numbplus = $number + 1;
return round($numbplus, $numzeros + 3) - 1;
}
Output is
Three zero places rounding number 1 : 0.123
Three zero places rounding number 2 : 0.0123
Three zero places rounding number 3 : 0.00012400000000001
Notice i cant do much about rounding for the third number being a little weird
You could use some increase rate which depend how much zeros you have after . and before first number. Instead round you could use substr if you need only cut after 3 character.
$arr = [0.12345, 0.012345, 0.0001239];
$outputArr = [];
foreach ($arr as $arrValue) {
$zeroCount = strspn($arrValue, "0", strpos($arrValue, ".")+1);
$increaseRate = pow(10, $zeroCount);
$outputArr[] = (float)(round($arrValue*$increaseRate, 3)/$increaseRate);
}
print_r($outputArr);