Message-ID: <1345066049.24355.YahooMailNeo@web142604.mail.bf1.yahoo.com>
Date: 2012-08-15T21:27:29Z
From: arun
Subject: Subsetting with missing data
In-Reply-To: <CAMt7gbPCQ4D_q8VuQV3rKuP7t8NJ9NkJMoacbCDD90RVxapafA@mail.gmail.com>
HI,
Try this:
subset(a,y==0)
#??? x y
#2?? 2 0
#5?? 5 0
#10 10 0
#or
subset(a,y%in%0)
#??? x y
#2?? 2 0
#5?? 5 0
#10 10 0
A.K.
----- Original Message -----
From: Robin Jeffries <rjeffries at ucla.edu>
To: r-help at r-project.org
Cc:
Sent: Wednesday, August 15, 2012 4:06 PM
Subject: [R] Subsetting with missing data
Simply put, I want to subset the data frame 'a' where 'y=0'.
> a <- as.data.frame(cbind(x=1:10, y=c(1,0,NA,1,0,NA,NA,1,1,0)))
> a
? ? x? y
1? 1? 1
2? 2? 0
3? 3 NA
4? 4? 1
5? 5? 0
6? 6 NA
7? 7 NA
8? 8? 1
9? 9? 1
10 10? 0
> names(a)
[1] "x" "y"
> table(a$y)
0 1
3 4
> table(a$y, useNA="always")
? 0? ? 1 <NA>
? 3? ? 4? ? 3
> b <- a[a$y==0,]
> b
? ? ? x? y
2? ? 2? 0
NA? NA NA
5? ? 5? 0
NA.1 NA NA
NA.2 NA NA
10? 10? 0
> is(a$y)
[1] "numeric" "vector"
Instead of only pulling the rows where a$y==0, i'm getting where they're 0,
OR NA. ? Again I feel like either something was changed when I wasn't
looking.. or I'm reaaaaaaly forgetting something important.
Thanks,
Robin Jeffries
MS, DrPH Candidate
Department of Biostatistics,
UCLA
530-633-STAT(7828)
rjeffries at ucla.edu
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