[R] i param in "for" loop does not takes zeros?

[Francisco J. Zagmutt]

Thanks to Rich, Douglas and Erin.  Off course the problem was the index!  I 
was looking at the wrong place!! Thanks for your help!

Francisco

>From: Rich FitzJohn <rich.fitzjohn at gmail.com>
>Reply-To: Rich FitzJohn <rich.fitzjohn at gmail.com>
>To: "Francisco J. Zagmutt" <gerifalte28 at hotmail.com>
>CC: R-help at stat.math.ethz.ch
>Subject: Re: [R] i param in "for" loop does not takes zeros?
>Date: Thu, 14 Apr 2005 09:36:21 +1200
>
>The for loop is not ignoring the zero at all, but the assignment is,
>since R indexes starting at 1, not zero.
>
> > sim <- c()
> > sim[0] <- 1
> > sim
>numeric(0)
>
>To run this loop this way, you need to add one to the index:
>for ( i in 0:5 )
>   sim[i+1] <- dbinom(i, 5, p)
>
>However, you'd be better off passing your vector of values directly to
>dbinom():
>
> > dbinom(0:5, 5, p)
>[1] 0.32768 0.40960 0.20480 0.05120 0.00640 0.00032
> > all(dbinom(0:5, 5, p) == sim)
>[1] TRUE
>
>Cheers,
>Rich
>
>On 4/14/05, Francisco J. Zagmutt <gerifalte28 at hotmail.com> wrote:
> > Hi all
> >
> > Is there any reason why the parameter i in a "for" loop ignores a value 
>of
> > zero?  For example
> >
> > sim=c()
> > p=.2
> > for(i in 0:5)
> >  {sim[i]=dbinom(i,5,p)
> >  }
> >
> > sim
> > [1] 0.40960 0.20480 0.05120 0.00640 0.00032
> >
> > In this example the quantile i= 0 was ignored since
> > dbinom(0,5,p)
> > [1] 0.32768
> >
> > The same behaviour occurs if I use a while loop to perform the same
> > calculation:
> > sim=c()
> > p=.2
> > i=0
> > while(i <6)
> >  {sim[i]=dbinom(i,5,p)
> >  i=i+1
> >  }
> > sim
> > [1] 0.40960 0.20480 0.05120 0.00640 0.00032
> >
> > How can I perform a loop passing a zero value parameter?  I know I can 
>use
> > an if statement for i<=0 but I was wondering why the loop is ignoring 
>the
> > zero value.
> >
> > Many thanks!
> >
> > Francisco
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide! 
>http://www.R-project.org/posting-guide.html
> >
>
>
>--
>Rich FitzJohn
>rich.fitzjohn <at> gmail.com   |    
>http://homepages.paradise.net.nz/richa183
>                       You are in a maze of twisty little functions, all 
>alike