[squeak-dev] Float differences
bert at freudenbergs.de
Wed Apr 25 20:28:07 UTC 2012
On 25.04.2012, at 13:20, Sven Van Caekenberghe wrote:
> The following code
> ((-10 to: 10) collect: [ :each | each * Float pi ])
> ((((-10 to: 10) collect: [ :each | each * Float pi ])
> collect: [ :each | each asString])
> collect: [ :each | Float readFrom: each ])
> returns true on Pharo 1.4 and false on Squeak 4.3
> Some of the Floats in the array compare equal, some not.
> Similary, (10 raisedTo: -100) asFloat
> prints as '1.0e-100' in Pharo and as ' 9.99999999999999e-101' in Squeak.
> I know that comparing Floats on equality is often dangerous and that #closeTo: is better.
> But I would like to understand how there could be such a difference between the two.
If you use storeString instead of asString it will be the same. E.g.
(10 raisedTo: -100) asFloat storeString
- Bert -
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