Re: [R] Attempting to recode elements contained in a list

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Thu 25 Aug 2005 - 16:28:11 EST

On Wed, 24 Aug 2005, Greg Blevins wrote:

> Hello R-Masters,
>
> I have a list 's' with three elements, as shown below. I want to recode
> a.a, a.a2, and a.a3 to NA if the value in a.a is less than 3.

I think s is a data frame, and you are looking at its printout. There is almost certainly no element a.a. Rather, the data frame has a column a, which is probably a matrix with three columns, a, a2 and a3. Use str(s) to be sure. Here is an attempt to create a similar object

> s <- data.frame(scan=letters[1:3], time=LETTERS[1:3])
> s$a <- array(runif(9)*6, dim=c(3,3), dimnames=list(NULL, c("a", "a2",
"a3")))
> s

   scan time a.a a.a2 a.a3

1    a    A 5.435430 1.283933 1.546180
2    b    B 5.169964 2.519836 1.568225
3    c    C 3.844045 2.318089 0.772869

If that is the case, you need

s$a[s$a[, "a"] < 3, ] <- NA

> I reivewed my Modern Applied Statistic Book, the online help and did
> some searching of R-help on the internet. I explored unlist and
> as.list.data.frame in an attempt to isolate the third element of the
> list s, but this was not helpful. Any help would be appreciated.
>
>> dim(s)
> [1] 342 3
>> names(s)
> [1] "scan" "time" "a"
>
>> s
> scan time a.a a.a2 a.a3
> 202 Plastic lids Plastic lids NaN NaN NaN
> 195 Plastic lids Cookware lids 44 31 58
> 205 Plastic lids Seasoning packets 9 4 20
> 191 Plastic lids Baking sheets 15 7 27
> 209 Plastic lids Utensils 9 4 20
> 194 Plastic lids Cell phones 0 0 7
> 193 Plastic lids Canned goods 0 0 7
> 197 Plastic lids Hand/dish towel 3 0 12
>
> Thank you.
>
> Greg Blevins
> The Market Solutions Group
>
> Windows xp, 2.1.1
>
> Gregory L. Blevins
> Vice President, Partner
> The Market Solutions Group, Inc.
> gblevins@marketsolutionsgroup.com
> Office phone: 612 392-3163
> Cell phone: 612 251-0232
> "What is at the beginning but a small error, swells to huge proportions at the close." Aristotle
>
> ______________________________________________
> 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
>

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

______________________________________________
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
Received on Thu Aug 25 16:31:55 2005

This archive was generated by hypermail 2.1.8 : Sun 23 Oct 2005 - 15:50:33 EST