[R] Significant digits for checking values of variable?

[David Afshartous]

All,

I'm witnessing some strange behavior when checking the values of one of my
variables.  My guess is that it has something to do with the number of
significant digits being represented, but perhaps not as my variable was
created from other variables that only had one decimal place.  See below.
I'm sure this is something basic, any suggestions much appreciated.

Cheers,
David


> visit.2.SEK.delta.baseline
 [1]  0.1 -0.7  0.8 -0.1 -0.5  0.8  0.7  0.2  0.4  0.3  0.6  0.6  0.3  0.8
0.8  0.3  0.4  0.8
> visit.2.SEK.delta.baseline > 0
 [1]  TRUE FALSE  TRUE FALSE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE
TRUE  TRUE  TRUE  TRUE  TRUE  TRUE
> visit.2.SEK.delta.baseline ==  .8
 [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
FALSE FALSE FALSE FALSE FALSE FALSE
### but some of the values are equal to .8

## here it is okay when I try to reproduce
>  junk = c(0.1, -0.7,0.8, -0.1, -0.5,  0.8,  0.7,  0.2,  0.4,  0.3,  0.6,  0.6,
0.3,  0.8,  0.8,  0.3,  0.4,  0.8 )
> junk == .8
 [1] FALSE FALSE  TRUE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE
FALSE  TRUE  TRUE FALSE FALSE  TRUE