[Newbies] Re: Rouding Floats up to a number of decimals - Method Finder

[nicolas cellier]

cdrick a écrit :
> I couldn't find such a function. I tryed in the method finder but find
> nothing:      MethodFinder methodFor: #(#(1.2288 3) 1.228).
> 
> Do somebody know if such a method exist ?
> 
> Meanwhile I did that:
> 
> Float>>trimAfter: aNumberOfDecimal   "roundAfter:"
> | number |
> number := 10 raisedTo: aNumberOfDecimal.
> ^(self * 10^aNumber) truncated "rounded" / 10^aNumber asFloat
> 
> and still MethodFinder methodFor: #(#(1.2288 3) 1.228) returns  '(no
> single method does that function) '
> whereas 1.2288 roundedAfter: 3 returns 1.229
> 
> Does anybody know what was wrong in my method finder use ?
> 
> Thanks
> 
> Cédrick
> 
> 
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Try with

MethodFinder methodFor: #(#(1001.2288 0.001) 1001.228).

It works even if (1001.2288 truncateTo: 0.001) ~= 1001.228, because of 
inexact arithmetic (in fact, it may depends which library is reading the 
Float; results are different if above decimal representation are rounded 
to nearest Float as SqNumberParser does).

The magic behind is that MethodFinder uses closeTo: rather than =, and 
this is right because no one should rely on Float equality after 
performing some inexact operations.

Nicolas