bccomp

(PHP 4, PHP 5)

bccompCompare deux nombres de grande taille

Description

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

Compare l'opérande left_operand avec l'opérande right_operand et retourne le résultat sous forme d'un entier.

Liste de paramètres

left_operand

L'opérande de gauche, sous la forme d'une chaîne de caractères.

right_operand

L'opérande de droite, sous la forme d'une chaîne de caractères.

scale

Le paramètre optionnel scale est utilisé pour définir le nombre de digits après la décimale qui sera utilisé dans la comparaison.

Valeurs de retour

Retourne 0 si les deux opérandes sont égaux, 1 si l'opérande left_operand est plus grand que l'opérande right_operand, -1 sinon.

Exemples

Exemple #1 Exemple avec bccomp()

<?php

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

?>
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User Contributed Notes 6 notes

up
5
Robert Lozyniak
4 years ago
Beware that negative zero does not compare equal to positive zero.
up
1
Anonymous
9 years ago
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);
   }
}
?>
up
1
Nitrogen
5 years ago
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.
up
-1
frank at booksku dot com
9 years ago
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;
}
?>
up
-1
github.com/alixaxel/phunction/
2 years ago
You can wrap this function with version_compare() to have support for operators and friendlier (boolean) return values.

<?php

function _bccomp($a, $b, $operator = '=')
{
    return
version_compare(bccomp($a, $b), 0, $operator);
}

var_dump(_bccomp(5, 3, '>=')); // true

?>

Still works with arbitrary length numbers.
up
-1
m dot kaczanowski at alianet dot pl
5 years ago
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;
}
?>
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