Equality with different precision #61

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1. nowackipawel commented on Feb 9, 2022

   

   nowackipawel

   on Feb 9, 2022

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   I am experiencing the same issue. I understand why it is working like this but this is not natural what you could expect.

   array(3) {
     [0]=>
     object(Decimal\Decimal)#184 (2) {
       ["value"]=>
       string(8) "0.000640"
       ["precision"]=>
       int(16)
     }
     [1]=>
     object(Decimal\Decimal)#185 (2) {
       ["value"]=>
       string(10) "0.00064000"
       ["precision"]=>
       int(18)
     }
     [2]=>
     int(-1)
   }
   
   

   and this is the code:

   var_dump([
   $transactionItem->tra_ass_id_from_amount,
   $entityCryptoAddress->amount,
   $transactionItem->tra_ass_id_from_amount->compareTo($entityCryptoAddress->amount)]
   ); 
   
2. nowackipawel commented on Feb 9, 2022

   

   nowackipawel

   on Feb 9, 2022

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   I thought trim will do the job, but as long as precision in one case is higher it is not working:/
3. rtheunissen commented on Feb 9, 2022

   

   rtheunissen

   on Feb 9, 2022

   Contributor

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   This is an easy fix if we can answer the fundamental question: how should we consider precision when evaluating equality? Looking at the Python documentation they have a few variations of compare, which is a direct mapping to mpdecimal, see https://www.bytereef.org/mpdecimal/doc/libmpdec/arithmetic.html#comparisons

   I think it makes sense here to compare strictly on the value, and have the precision affect calculation and conversion only. In that case your examples of 0.000640 and 0.00064000 would be equal. I'm open to making that change in 2.x which is currently still alpha and not documented on http://php-decimal.io

   👍React with 👍1Reacted by rx80
4. speller commented on Jul 12, 2023

   

   speller

   on Jul 12, 2023

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   I'm voting for this fix!

   👍React with 👍1Reacted by rx80