Re: Float comparison

Hi, Jonathan Bond-Caron wrote:

Hi, I'm new to the PHP internals list and I'm posting an issue I'm sure has been mentioned before -- float comparison I'd like to know if there are reasons not to change the default behavior when comparing floats. i.e. This would seem logical to me:

                $test = 19.6*100;

                if((float)(string)$test == (double)1960)

                                echo "GOOD BEHAVIOR";

                
                // Implicitely convert the float to string then float (en_US

locale)

                if($test == (double)1960)

                                echo "THIS SHOULD PASS by casting

(float)(string)$test internally...";

                else

                                echo "NOT GOOD BEHAVIOR";

                // Exact comparison would still fail

                if($test !== (double)1960)

                                echo "GOOD BEHAVIOR";

Any reason why $test == (double)1960 should fail? I realized we are comparing two floats, but couldn't php internally convert to string then float - for the non strict (===) case Thanks

Never compare directly floats but subtract one from the other and check whether the difference is bigger or smaller than a small predefined number. Regards, Andrey -- Andrey Hristov, Connectors Software Developer Sun Microsystems GmbH, Sonnenallee 1, 85551 Kirchheim-Heimstetten Amtsgericht Muenchen: HRB161028 Geschaeftsfuehrer: Thomas Schroeder, Wolfgang Engels, Dr. Roland Boemer Vorsitzender des Aufsichtsrates: Martin Haering