R help - Dec 2010 - with(data.frame,ifelse(___,___,___))

Hello, All,

Mac OS 10.6.5
R64 2.11.1

This works as expected:

f1 = c(0.084, 0.099, 0)
data= data.frame(f1)
data$f1=with(data,ifelse(f1==0, 0.0001, f1))
data

     f1
1 0.0840
2 0.0990
3 0.0001

Substituting ''f1==0'' with ''T'' produces the
expected result:

f1 = c(0.084, 0.099, 0)
data= data.frame(f1)
data$f1=with(data,ifelse(T, 0.0001, f1))
data

     f1
1 1e-04
2 1e-04
3 1e-04

But, substituting ''f1==0''  or ''T'' with
''F'' does not produce the expected result:

f1 = c(0.084, 0.099, 0)
data= data.frame(f1)
data$f1=with(data,ifelse(F, 0.0001, f1))
data

     f1
1 0.084
2 0.084
3 0.084

I would expect this:
     f1
1 0.084
2 0.099
3 0

Is with(data.frame,ifelse(___,___,___)) broken, or does my interpretation of it
need fixing?

Thank you for your time.

Jim

	[[alternative HTML version deleted]]

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Jim Moon
> Sent: Wednesday, December 22, 2010 5:05 PM
> To: R-help at r-project.org
> Subject: [R] with(data.frame,ifelse(___,___,___))
> 
> Hello, All,
> 
> Mac OS 10.6.5
> R64 2.11.1
> 
> This works as expected:
> 
> f1 = c(0.084, 0.099, 0)
> data= data.frame(f1)
> data$f1=with(data,ifelse(f1==0, 0.0001, f1))
> data
> 
>      f1
> 1 0.0840
> 2 0.0990
> 3 0.0001
> 
> Substituting 'f1==0' with 'T' produces the expected result:
> 
> f1 = c(0.084, 0.099, 0)
> data= data.frame(f1)
> data$f1=with(data,ifelse(T, 0.0001, f1))
It produces those results accidently.  Look
at the output of the ifelse call, before you
stuff it into data$f1:
  > ifelse(TRUE, 0.0001, data$f1)
  [1] 1e-04
The output of ifelse(condition,ifTrue,ifFalse)
is the length of the condition argument and has
nothing to do with the length of the ifTrue
or ifFalse arguments.  `$<-.data.frame`(x,name,value)
will expand the value argument to the nrow(x).

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com 
> data
> 
>      f1
> 1 1e-04
> 2 1e-04
> 3 1e-04
> 
> But, substituting 'f1==0'  or 'T' with 'F' does not
produce
> the expected result:
> 
> f1 = c(0.084, 0.099, 0)
> data= data.frame(f1)
> data$f1=with(data,ifelse(F, 0.0001, f1))
> data
> 
>      f1
> 1 0.084
> 2 0.084
> 3 0.084
> 
> I would expect this:
>      f1
> 1 0.084
> 2 0.099
> 3 0
> 
> Is with(data.frame,ifelse(___,___,___)) broken, or does my 
> interpretation of it need fixing?
> 
> Thank you for your time.
> 
> Jim
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>