[R] "match" and "which" give NA for some values, but not others

[Daniel Nordlund]

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of Heemun Kwok
> Sent: Tuesday, July 26, 2011 8:50 PM
> To: r-help at r-project.org
> Subject: [R] "match" and "which" give NA for some values, but not others
> 
> Hello list,
> I am having trouble with "match" and "which" giving a NA result for some
> values, but not others.  Here is a simple example:
> 
> > aaa <- seq(0,1,by=0.05)
> 
> > aaa
>  [1] 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65
> 0.70
> [16] 0.75 0.80 0.85 0.90 0.95 1.00
> 
> > match(0.5,aaa)
> [1] 11
> 
> > match(0.6,aaa)
> [1] NA
> 
> > which(aaa==0.5)
> [1] 11
> 
> > which(aaa==0.6)
> integer(0)
> 
> > sessionInfo()
> R version 2.12.2 (2011-02-25)
> Platform: i386-pc-mingw32/i386 (32-bit)
> 
> Am I missing something? Any thoughts?
> 
> Thank you,
> Heemun
> 
> 

Take a look at R FAQ 7.31.

Hope this is helpful,

Dan

Daniel Nordlund
Bothell, WA USA