My preferred solution would be to use the select option of the subset function.
> data ( iris )
> names ( iris )
[1] "Sepal.Length" "Sepal.Width" "Petal.Length"
"Petal.Width" "Species"
# KEEP-like way > iris_subset_by_keep <- subset ( iris, select = c(
"Sepal.Length", "Species" ) )
# DROP-like way> iris_subset_by_drop <- subset ( iris, select = c ( -Sepal.Width,
-Petal.Length, -Petal.Width) )
> identical ( iris_subset_by_keep , iris_subset_by_drop )
[1] TRUE
> names ( iris_subset_by_keep )
[1] "Sepal.Length" "Species" >
p.s.
data NeweRa ( drop = SAS );
set Much_Better;
eRic
----- Original message -----
From: "Wensui Liu" <liuwensui at gmail.com>
To: sarjinder at yahoo.com
Cc: r-help at r-project.org
Date: Sat, 19 Dec 2009 20:19:51 -0500
Subject: Re: [R] DROP and KEEP statements in R
drop example.> data(iris)
> summary(iris)
Sepal.Length Sepal.Width Petal.Length Petal.Width
Min. :4.300 Min. :2.000 Min. :1.000 Min. :0.100
1st Qu.:5.100 1st Qu.:2.800 1st Qu.:1.600 1st Qu.:0.300
Median :5.800 Median :3.000 Median :4.350 Median :1.300
Mean :5.843 Mean :3.057 Mean :3.758 Mean :1.199
3rd Qu.:6.400 3rd Qu.:3.300 3rd Qu.:5.100 3rd Qu.:1.800
Max. :7.900 Max. :4.400 Max. :6.900 Max. :2.500
Species
setosa :50
versicolor:50
virginica :50
> iris$Species <- NULL
> summary(iris)
Sepal.Length Sepal.Width Petal.Length Petal.Width
Min. :4.300 Min. :2.000 Min. :1.000 Min. :0.100
1st Qu.:5.100 1st Qu.:2.800 1st Qu.:1.600 1st Qu.:0.300
Median :5.800 Median :3.000 Median :4.350 Median :1.300
Mean :5.843 Mean :3.057 Mean :3.758 Mean :1.199
3rd Qu.:6.400 3rd Qu.:3.300 3rd Qu.:5.100 3rd Qu.:1.800
Max. :7.900 Max. :4.400 Max. :6.900 Max. :2.500
On Sat, Dec 19, 2009 at 3:21 PM, <sarjinder at yahoo.com> wrote:
> What is equivalent to DROP or KEEP statements of SAS in R?
>
> --
> This message was sent on behalf of sarjinder at yahoo.com at
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--
=============================WenSui Liu
Blog : statcompute.spaces.live.com
Tough Times Never Last. But Tough People Do. - Robert Schuller
=============================
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