php float unrounded truncation of floating point string method summaries
- 2020-10-23 20:54:39
- OfStack
There are several ways to intercept floating point in php:
1. float round (float $val [, int $precision]) returns val rounding precision (the number of digits after the decimal point) to the specified precision. precision can also be negative or zero (the default).
echo round(4.3) //4
2, string sprintf (string $format [, mixed $args [, mixed $...]]) returns a string of formatted data
$a=12.338938438;
echo sprintf("%.5f",$a) // Results: 12.33894
$a=12.3312356;
echo sprintf("%.5f",$a);//12.33124
echo sprintf("%f",$a);//331236 After the default decimal point 6 position
3, string number_format (float $number, int $decimals, string $dec_point, string $thousands_sep)
$number = 1234.5678;
$english_format_number = number_format($number, 2, '.', '');
echo $english_format_number ; // 1234.57
So all of these things are done automatically, and sometimes you don't need to round 4 or round 5, so what do you do? You don't have a good idea. Who knows, you can tell me 1.
I wrote a troublesome function, and I wrote it down
function getFloatValue($f,$len)
{
$tmpInt=intval($f);
$tmpDecimal=$f-$tmpInt;
$str="$tmpDecimal";
$subStr=strstr($str,'.');
if(strlen($subStr)<$len+1)
{
$repeatCount=$len+1-strlen($subStr);
$str=$str."".str_repeat("0",$repeatCount);
}
return $tmpInt."".substr($str,1,1+$len);
}
echo getFloatValue(12.99,4) //12.9900
echo getFloatValue(12.9232555553239,4) //12.9232