Hi,
set.seed(24)
dat1<- data.frame(ID=1:500,value=rnorm(500))
dat1 <- dat1[order(-dat1$value),]
row.names(dat1)<-1:nrow(dat1) ########
indx<-round(quantile(as.numeric(row.names(dat1)),probs=c(0.05,0.20,0.50,1)))
indx1<-findInterval(row.names(dat1),indx,rightmost.closed=TRUE)
dat1$SEGMENT<- as.character(factor(indx1,labels=c("Top 5%","5 to 20","20 to
50", "Bottom 50")))
A.K.
Hi Arun Kirshna,
I have tested your method and it will work for me.
I only run into one problem. Before I want to do this operation I have sorted
my data frame so my rownumbers ar not subsequent.
You can see if you first order your example data frame like:
dat1 <- dat1[order(-dat1$value),]
head(dat1)
ID value SEGMENT
237 237 3.538552 20 to 50
21 21 3.376149 Top 5%
421 421 3.015634 Bottom 50
339 339 2.855991 Bottom 50
119 119 2.589574 20 to 50
12 12 2.512276 Top 5%
Do you have a solution for this?
----- Original Message -----
From: arun <smartpink...@yahoo.com>
To: Dark <i...@software-solutions.nl>
Cc: R help <r-help@r-project.org>
Sent: Wednesday, July 31, 2013 7:48 AM
Subject: Re: [R] Add a column to a data frame with value based on the
percentile of the row
Hi,
May be this helps:
set.seed(24)
dat1<- data.frame(ID=1:500,value=rnorm(500))
indx<-round(quantile(as.numeric(row.names(dat1)),probs=c(0.05,0.20,0.50,1)))
indx1<-findInterval(row.names(dat1),indx,rightmost.closed=TRUE)
dat1$SEGMENT<- as.character(factor(indx1,labels=c("Top 5%","5 to 20","20 to
50", "Bottom 50")))
head(dat1)
# ID value SEGMENT
#1 3 -0.7859574 Top 5%
#2 3 1.0117428 Top 5%
#3 8 -2.1558035 Top 5%
#4 6 1.7803880 Top 5%
#5 7 0.4192816 Top 5%
#6 10 -1.0142512 Top 5%
tail(dat1)
# ID value SEGMENT
#495 1 0.3571848 Bottom 50
#496 9 -1.1971854 Bottom 50
#497 5 0.3544896 Bottom 50
#498 8 -0.1562356 Bottom 50
#499 8 -0.2994321 Bottom 50
#500 8 -0.4170319 Bottom 50
A.K.
----- Original Message -----
From: Dark <i...@software-solutions.nl>
To: r-help@r-project.org
Cc:
Sent: Wednesday, July 31, 2013 5:37 AM
Subject: [R] Add a column to a data frame with value based on the percentile of
the row
Hi all,
I think this should be an easy question for the guru's out here.
I have this large data frame (2.500.000 rows, 15 columns) and I want to add
a column named "SEGMENT" to it.
The first 5% rows (first 125.000 rows) should have the value "Top 5%" in the
SEGMENT column
Then the rows from 5% to 20% should have the value "5 to 20"
Then 20-50% should have the value "20 to 50"
And the last 50% of the rows should have the value "Bottom 50"
What is the easiest way of doing this? I was thinking of using quantile but
then I should have some rownumber column.
Regards Derk
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