[R] Extracting data using subset function

[Rolf Turner]

On Sun, 5 Feb 2023 19:37:03 +0530
Upananda Pani <upananda.pani using gmail.com> wrote:

> Dear All,
> 
> I want to create a vector p and extract first 20 observations using
> subset function based on logical condition.
> 
> My code is below
> 
> p <- 0:100
> 
> I know i can extract the first 20 observations using the following
> command.
> 
> q <- p[1:20]
> 
> But I want to extract the first 20 observations using subset function
> which requires a logical condition. I am not able to frame the
> logical condition.
> 
> The code should be
> 
> q <- subset(p, logical condition)
> 
> I am not able to do it. Please let me know what you think.

I think that you are manufacturing an unnecessary difficulty.  If you
want the first 20 entries of p, use p[1:20]!!!

However, if you obdurately *insist* on using subset() you could do

    subset(p,(1:length(p)) <= 20)

This works, but makes a mountain out of a molehill.

cheers,

Rolf Turner

-- 
Honorary Research Fellow
Department of Statistics
University of Auckland
Stats. Dep't. phone: +64-9-373-7599 ext. 89622
Home phone: +64-9-480-4619