Christopher Desjardins
2013-Aug-16 19:02 UTC
[R] Randomly drop a percent of data from a data.frame
Hi, I have the following data.> set.seed(6245) > data <- data.frame(x1=rnorm(5),x2=rnorm(5),x3=rnorm(5),x4=rnorm(5)) > round(data,digits=3)x1 x2 x3 x4 1 0.482 1.320 -0.859 -0.142 2 -0.753 -0.041 -0.063 0.886 3 0.028 -0.256 -0.069 0.354 4 -0.086 0.475 0.244 0.781 5 0.690 -0.181 1.274 1.633 What I would like to do is drop 20% of the data. But I want this 20% to only come from dropping data from x3 and x4. It doesn't have to be evenly, i.e. I don't care to drop 2 from x3 and 2 from x4 or make sure only one observation has missing data on only one variable. I just want to drop 20% of the data through x3 and x4 only. In other words, x1 x2 x3 x4 1 0.482 1.320 -0.859 NA 2 -0.753 -0.041 -0.063 0.886 3 0.028 -0.256 NA 0.354 4 -0.086 0.475 NA 0.781 5 0.690 -0.181 NA 1.633 OR x1 x2 x3 x4 1 0.482 1.320 NA -0.142 2 -0.753 -0.041 -0.063 0.886 3 0.028 -0.256 NA NA 4 -0.086 0.475 0.244 NA 5 0.690 -0.181 1.274 1.633 OR x1 x2 x3 x4 1 0.482 1.320 -0.859 -0.142 2 -0.753 -0.041 -0.063 NA 3 0.028 -0.256 -0.069 NA 4 -0.086 0.475 0.244 NA 5 0.690 -0.181 1.274 NA ETC. are all fine. Any ideas how I can do this? Chris [[alternative HTML version deleted]]
Hi,
May be this helps:
#data1 (changed `data` to `data1`)
set.seed(6245)
?data1 <- data.frame(x1=rnorm(5),x2=rnorm(5),x3=rnorm(5),x4=rnorm(5))
?data1<- round(data1,digits=3)
data2<- data1
data1[,3:4]<-lapply(data1[,3:4],function(x){x1<-
match(x,sample(unlist(data1[,3:4]),round(0.8*length(unlist(data1[,3:4])))));x[is.na(x1)]<-NA;x})
?data1
#????? x1???? x2???? x3???? x4
#1? 0.482? 1.320???? NA -0.142
#2 -0.753 -0.041 -0.063? 0.886
#3? 0.028 -0.256 -0.069? 0.354
#4 -0.086? 0.475? 0.244? 0.781
#5? 0.690 -0.181? 1.274? 1.633
#or
data2[,3:4]<-lapply(data2[,3:4],function(x){x1<-
match(x,sample(unlist(data2[,3:4]),round(0.8*length(unlist(data2[,3:4])))));x[is.na(x1)]<-NA;x})
?data2
#????? x1???? x2???? x3???? x4
#1? 0.482? 1.320 -0.859 -0.142
#2 -0.753 -0.041???? NA???? NA
#3? 0.028 -0.256 -0.069? 0.354
#4 -0.086? 0.475? 0.244? 0.781
#5? 0.690 -0.181? 1.274? 1.633
A.K.
----- Original Message -----
From: Christopher Desjardins <cddesjardins at gmail.com>
To: "r-help at r-project.org" <r-help at r-project.org>
Cc:
Sent: Friday, August 16, 2013 3:02 PM
Subject: [R] Randomly drop a percent of data from a data.frame
Hi,
I have the following data.
> set.seed(6245)
> data <- data.frame(x1=rnorm(5),x2=rnorm(5),x3=rnorm(5),x4=rnorm(5))
> round(data,digits=3)
? ? ? x1? ? x2? ? x3? ? x4
1? 0.482? 1.320 -0.859 -0.142
2 -0.753 -0.041 -0.063? 0.886
3? 0.028 -0.256 -0.069? 0.354
4 -0.086? 0.475? 0.244? 0.781
5? 0.690 -0.181? 1.274? 1.633
What I would like to do is drop 20% of the data. But I want this 20% to
only come from dropping data from x3 and x4. It doesn't have to be evenly,
i.e. I don't care to drop 2 from x3 and 2 from x4 or make sure only one
observation has missing data on only one variable. I just want to drop 20%
of the data through x3 and x4 only.? In other words,
? ? ? x1? ? x2? ? x3? ? x4
1? 0.482? 1.320 -0.859 NA
2 -0.753 -0.041 -0.063? 0.886
3? 0.028 -0.256? ? ? NA? 0.354
4 -0.086? 0.475? ? ? NA? 0.781
5? 0.690 -0.181? ? ? NA? 1.633
OR
? ? ? x1? ? x2? ? x3? ? x4
1? 0.482? 1.320? ? NA -0.142
2 -0.753 -0.041 -0.063? 0.886
3? 0.028 -0.256? ? ? NA? NA
4 -0.086? 0.475? 0.244? NA
5? 0.690 -0.181? 1.274? 1.633
OR
? ? ? x1? ? x2? ? x3? ? x4
1? 0.482? 1.320 -0.859 -0.142
2 -0.753 -0.041 -0.063? ? NA
3? 0.028 -0.256 -0.069? ? NA
4 -0.086? 0.475? 0.244? ? NA
5? 0.690 -0.181? 1.274? ? NA
ETC. are all fine.
Any ideas how I can do this?
Chris
??? [[alternative HTML version deleted]]
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