From: Rich FitzJohn <rich.fitzjohn_at_gmail.com>

Date: Thu 14 Apr 2005 - 07:36:21 EST

Date: Thu 14 Apr 2005 - 07:36:21 EST

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@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@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 ______________________________________________ R-help@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.htmlReceived on Thu Apr 14 07:41:37 2005

*
This archive was generated by hypermail 2.1.8
: Fri 03 Mar 2006 - 03:31:08 EST
*