Summary of PHP rounding and interception methods of floating point strings

In phpInterception of floating point typeThere are roughly the following methods:

1. float round (float $val [, int $precision]) returns val according to the specified precision precision (the number of decimal digits after the decimal point) rounded. precision can also be negative or zero (default).

echo round(4.3) //4

2. string sprintf ( string $format [, mixed $args [, mixed $... ]] ) returns the string of formatted data

$a=12.338938438; 
echo sprintf("%.5f",$a) //结果：12.33894  

$a=12.3312356; 
echo sprintf("%.5f",$a);//12.33124 
echo sprintf("%f",$a);//331236  默认小数点后6位

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

The above are automatically rounded, and sometimes rounding is not required. , what should I do? I haven’t thought of a good solution. If anyone knows, can you tell me.

I wrote a troublesome function and recorded it

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

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