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bccomp

(PHP 4, PHP 5)

bccompVergleich zweier Zahlen beliebiger Genauigkeit

Beschreibung

int bccomp ( string $left_operand , string $right_operand [, int $scale ] )

Vergleicht den left_operand mit dem right_operand und gibt das Ergebnis als Integer-Wert zurück.

Parameter-Liste

left_operand

Der linke Operand in Stringform.

right_operand

Der rechte Operand in Stringform.

scale

Der optionale scale-Parameter wird verwendet, um die Anzahl der Dezimalstellen nach dem Komma anzugeben, die für den Vergleich herangezogen werden sollen.

Rückgabewerte

Gibt 0 zurück, wenn beide Operatoren gleich sind, 1, wenn left_operand größer ist als right_operand, und andernfalls -1.

Beispiele

Beispiel #1 bccomp()-Beispiel

<?php

echo bccomp('1''2') . "\n";   // -1
echo bccomp('1.00001''1'3); // 0
echo bccomp('1.00001''1'5); // 1

?>

5 BenutzerBeiträge:
- Beiträge aktualisieren...
Robert Lozyniak
17.02.2010 7:04
Beware that negative zero does not compare equal to positive zero.
Nitrogen
21.07.2009 15:23
I made this to compare an unlimited size of numbers..

This could be useful for those without the BCMath extension.

It allows decimals, and option $Scale parameter.  If $Scale isn't specified, then it'll automatically adjust to the correct number of decimals to compare.

<?php

function Comp($Num1,$Num2,$Scale=null) {
 
// check if they're valid positive numbers, extract the whole numbers and decimals
 
if(!preg_match("/^\+?(\d+)(\.\d+)?$/",$Num1,$Tmp1)||
     !
preg_match("/^\+?(\d+)(\.\d+)?$/",$Num2,$Tmp2)) return('0');

 
// remove leading zeroes from whole numbers
 
$Num1=ltrim($Tmp1[1],'0');
 
$Num2=ltrim($Tmp2[1],'0');

 
// first, we can just check the lengths of the numbers, this can help save processing time
  // if $Num1 is longer than $Num2, return 1.. vice versa with the next step.
 
if(strlen($Num1)>strlen($Num2)) return(1);
  else {
    if(
strlen($Num1)<strlen($Num2)) return(-1);

   
// if the two numbers are of equal length, we check digit-by-digit
   
else {

     
// remove ending zeroes from decimals and remove point
     
$Dec1=isset($Tmp1[2])?rtrim(substr($Tmp1[2],1),'0'):'';
     
$Dec2=isset($Tmp2[2])?rtrim(substr($Tmp2[2],1),'0'):'';

     
// if the user defined $Scale, then make sure we use that only
     
if($Scale!=null) {
       
$Dec1=substr($Dec1,0,$Scale);
       
$Dec2=substr($Dec2,0,$Scale);
      }

     
// calculate the longest length of decimals
     
$DLen=max(strlen($Dec1),strlen($Dec2));

     
// append the padded decimals onto the end of the whole numbers
     
$Num1.=str_pad($Dec1,$DLen,'0');
     
$Num2.=str_pad($Dec2,$DLen,'0');

     
// check digit-by-digit, if they have a difference, return 1 or -1 (greater/lower than)
     
for($i=0;$i<strlen($Num1);$i++) {
        if((int)
$Num1{$i}>(int)$Num2{$i}) return(1);
        else
          if((int)
$Num1{$i}<(int)$Num2{$i}) return(-1);
      }

     
// if the two numbers have no difference (they're the same).. return 0
     
return(0);
    }
  }
}

$A="10.50002";
$B="10.50001";

printf("  Comp(%s,%s); // %s\r\n",$A,$BComp($A,$B));
printf("BCComp(%s,%s); // %s\r\n",$A,$B,BCComp($A,$B));

/*
    Comp(10.50002,10.50001); // 1
  BCComp(10.50002,10.50001); // 0 (BCComp has a default decimal scale of 0, unless specified)
*/

?>

I tried to make this behave like BCComp..

The only difference being mine will compare the decimals by default.. BCComp won't..
.. unless, of course, you specify the amount of decimals to include in the process.
Enjoy,
Nitrogen.
m dot kaczanowski at alianet dot pl
11.03.2009 15:35
Improvement of functions bcmax() and bcmin() originaly written by frank at booksku dot com

<?php

function bcmax() {
 
$args = func_get_args();
  if (
count($args)==0) return false;
 
$max = $args[0];
  foreach(
$args as $value) {
    if (
bccomp($value, $max)==1) {
     
$max = $value;
    }
  }
  return
$max;
}

function
bcmin() {
 
$args = func_get_args();
  if (
count($args)==0) return false;
 
$min = $args[0];
  foreach(
$args as $value) {
    if (
bccomp($min, $value)==1) {
     
$min = $value;
    }
  }
  return
$min;
}
?>
frank at booksku dot com
5.10.2005 0:41
I slapped together min() and max() functions using bccomp().  While min() and max() only take an arbitrary number of args (i.e. max(1, 5, 1235, 12934, 66)) bccomp only takes 2.

Note that this doesn't take into account $scale.

<?php

function bcmax() {
 
$max = null;
  foreach(
func_get_args() as $value) {
    if (
$max == null) {
     
$max = $value;
    } else if (
bccomp($max, $value) < 0) {
     
$max = $value;
    }
  }
  return
$max;
}

function
bcmin() {
 
$min = null;
  foreach(
func_get_args() as $value) {
    if (
$min == null) {
     
$min = $value;
    } else if (
bccomp($min, $value) > 0) {
     
$min = $value;
    }
  }
  return
$min;
}
?>

11.02.2005 23:03
Note that the above function defeats the purpose of BCMath functions, for it uses the 'conventional' < operator.
Instead, it should be:
<?php
function my_bccomp_zero($amount, $scale)
{
   if (@
$amount{0}=="-")
   {
       return
bccomp($amount, '-0.0', $scale);
   }
   else
   {
       return
bccomp($amount, '0.0', $scale);
   }
}
?>



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