ruby: converting from float to integer in ruby produces strange results

Question

ree-1.8.7-2010.02 :003 > (10015.8*100.0).to_i
 => 1001579 
ree-1.8.7-2010.02 :004 > 10015.8*100.0
 => 1001580.0 
ree-1.8.7-2010.02 :005 > 1001580.0.to         


        

Answer 1

Due to truncation error in float calculation, 10015.8*100.0 is actually calculated as 1001579.999999... So if you simply apply to_i, it cuts off the decimal part and returns 1001579