From murdoch at stats.uwo.ca  Thu Oct 27 15:40:18 2005
From: murdoch at stats.uwo.ca (murdoch@stats.uwo.ca)
Date: Thu, 27 Oct 2005 15:40:18 +0200 (CEST)
Subject: [Rd] Critical Bug in type conversions: as.integer, trunc,
	... (PR#8257)
Message-ID: <20051027134018.D34F221ED6@slim.kubism.ku.dk>

On 10/27/2005 9:24 AM, g.toedt at dkfz.de wrote:
> Full_Name: Grischa T?dt
> Version: 2.1.1
> OS: windows XP
> Submission from: (NULL) (192.108.25.32)
> 
> 
> I have a strange behaviour in R, looks like type conversions are messed up.

This is not a bug, it's normal behaviour for floating point values, 
discussed in the FAQ item on "7.31 Why doesn't R think these numbers are 
equal?"

Duncan Murdoch

> 
> To reproduce:
> 
> expected:
>> typeof(3)
> [1] "double"
> 
>> as.integer(3)
> [1] 3
> 
> !!!! strange:
>> typeof((0.3/0.1))
> [1] "double"
> 
>> as.integer((0.3/0.1))
> [1] 2
> 
> also for trunc:
>>trunc(c(5,7))
>>c(0.5,0.7)/c(0.1,0.1)
> 
> and now watch the amazing!!!!:
>>trunc((c(0.5,0.7)/c(0.1,0.1)))
> 
> 
> 
> 
> My R-Version:
> platform i386-pc-mingw32
> arch     i386           
> os       mingw32        
> system   i386, mingw32  
> status                  
> major    2              
> minor    1.1            
> year     2005           
> month    06             
> day      20             
> language R
> 
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel



[Rd] Critical Bug in type conversions: as.integer, trunc, ... (PR#8257)
murdoch@stats.uwo.ca