R help - Mar 2008 - Bug check (possibly in seq()). RGui 2.6.2 (2008-02-08)

Hello All,

I'm new to R, but I can't account for the results from the simple script
below and it looks simple enough.

Description: When A is generated by seq(), A[A==x] incorrectly returns
numeric(0) for some values of x (in A) but not others.

##########################
A<-seq(0,1,by=.05)

#These return numeric(0), but others in the set return the correct value
A[A==.3]
A[A==.6]
A[A==.7]
A[A==.15]
A[A==.35]
A[A==.85]
A[A==.95] #A[20]

# This works fine
B<-seq(0,1,by=.05)
A[A==B]

# This also works fine
A<-c(0,.05,.1,.15,.2,.25,.30,.35,.40,.45,
    .50,.55,.6,.65,.7,.75,.8,.85,.9,.95,1)
A[A==.3]
##########################

R, RGui 2.6.2 (2008-02-08)
Windows XP Professional SP 2
Pentium(R) D CPU 2.80GHz, 2G RAM

Hoping someone else can reproduce it.

Regards,
Eric Set

See the R-FAQ 7.31 Why doesn't R think these numbers
are equal?  for the likely reason.
--- SET Eric Brendan <ericset at ust.hk> wrote:
> Hello All,
> 
> I'm new to R, but I can't account for the results
> from the simple script
> below and it looks simple enough.
> 
> Description: When A is generated by seq(), A[A==x]
> incorrectly returns
> numeric(0) for some values of x (in A) but not
> others.
> 
> ##########################
> A<-seq(0,1,by=.05)
> 
> #These return numeric(0), but others in the set
> return the correct value
> A[A==.3]
> A[A==.6]
> A[A==.7]
> A[A==.15]
> A[A==.35]
> A[A==.85]
> A[A==.95] #A[20]
> 
> # This works fine
> B<-seq(0,1,by=.05)
> A[A==B]
> 
> # This also works fine
> A<-c(0,.05,.1,.15,.2,.25,.30,.35,.40,.45,
>     .50,.55,.6,.65,.7,.75,.8,.85,.9,.95,1)
> A[A==.3]
> ##########################
> 
> R, RGui 2.6.2 (2008-02-08)
> Windows XP Professional SP 2
> Pentium(R) D CPU 2.80GHz, 2G RAM
> 
> Hoping someone else can reproduce it.
> 
> Regards,
> Eric Set
> 
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