[R] subsetting - questions

Muhuri, Pradip (SAMHSA/CBHSQ)
2012-11-24T05:02:31Z

Hi Jorge,

I could use subset(). But, I wanted to minimize coding.

Thanks,

Pradip
________________________________________
From: Jorge I Velez [jorgeivanvelez at gmail.com]
Sent: Friday, November 23, 2012 10:02 PM
To: Muhuri, Pradip (SAMHSA/CBHSQ)
Cc: r-help at r-project.org
Subject: Re: [R] subsetting - questions

Hi Pradip,

It is easier to use subset().  Check ?subset for some examples and pay special
attention to the "select" parameter.  By the way, do not call your
data "df" as it is already a function.

Best,
Jorge.-


On Sat, Nov 24, 2012 at 1:55 PM, Muhuri, Pradip (SAMHSA/CBHSQ) <> wrote:

Hello,

I have two very basic questions (console attached):

1) What am I getting an error message for  # 5 and # 7 ?
2) How to fix the code?

I would appreciate receiving your help.

Thanks,

Pradip Muhuri



###### Reproducible Example  #####

N <- 100
set.seed(13)
df<-data.frame(matrix(sample(c(1:10),N, replace=TRUE),ncol=5))

keep_var <- c("X1", "X2")
drop_var <- c("X3", "X4", "X5")


df[df$X1>=8,] [,1:2]                   #1
df[df$X1>=8,] [,-c(3,4,5)]             #2
df[df$X1>=8,] [,c(-3,-4,-5)]           #3
df[df$X1>=8,] [,c("X1", "X2")]         #4
df[df$X1>=8,] [,-c("X3", "X4", "X5")]  #5  DOES
NOT WORK
df[df$X1>=8,] [,keep_var]              #6
df[df$X1>=8,] [, !drop_var]            #7   DOES NOT WORK

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