[R] The use of F for False and T for True
s.blomberg1 at uq.edu.au
Mon Nov 17 02:41:16 CET 2008
It is better programming practice to use FALSE for false and TRUE for
true, and not F and T. This is because it is quite legal to do this:
T <- FALSE
F <- TRUE
or any other assignment. If you re-assign T or F (which are set to TRUE
and FALSE at the beginning of a session), you run into the sort of
problem that you have discovered.
Also, there is the F and t distributions, and the t() function, so
having variables called F and T may lead to further confusion. If you
mean FALSE, say FALSE. If you mean TRUE, say TRUE.
On Sun, 2008-11-16 at 17:56 -0700, David C. Howell wrote:
> Sampling with and without replacement
> I seem unable to use "replace = F" when I want to sample without
> replacement. I would think
> that it comes down to "F is not a legitimate abbreviation for FALSE."
> except that
> Dalgaard (p. 118) uses F for FALSE and it works
> "pairwise.t.test(folate, ventilation, pool.sd = F)"
> I am having trouble when I try to sample a vector without replacement.
> The following code illustrates my problem.
> >b <- c(1:8)
>  7 8 3 5 1 6 2 4 # That works correctly--no replacement
> (This would be my preferred form, but when I look at the code later it
> is helpful to know
> explicitly how I did the sampling.)
> > sample(b, replace = T)
>  7 5 6 2 5 5 4 7 # That is also correct--replacement
> > sample(b, replace = F)
>  1 7 3 7 3 4 6 5 # There are two 3s and two 7s, so there was
> >sample(b, replace = FALSE)
>  8 1 3 2 5 6 7 4 # That works just fine
> >sample(b, replace = "F")
>  5 3 2 8 4 1 7 6 # quoting the F is fine.
> If it is OK to replace TRUE with T, why can't I replace FALSE with F?
> I have a similar problem if I write data <= read.table(file.choose(),
> header = F)
> I'm using a Windows machine with version 2.8.0, but I'm sure that this
> is not a machine specific problem.
> Dave Howell
Simon Blomberg, BSc (Hons), PhD, MAppStat.
Lecturer and Consultant Statistician
Faculty of Biological and Chemical Sciences
The University of Queensland
St. Lucia Queensland 4072
Room 320 Goddard Building (8)
T: +61 7 3365 2506
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