CODEWITHSUNDEEP
r
Aystealthy
Aystealthy

Reputation: 169

How to see/count the number of unique rows in a dataframe

For reference

library(vcd)
data(Arthritis)
Art = Arthritis[c("Treatment", "Sex", "Age")]

I want to find out the number of matching attributes in a data frame.

For example

Adj Name Verb
Red John Jumps
Blue John Sleeps
Red John Jumps
Red Smith Jumps
Red Smith Walks

In the end, I want to see:

Adj Name Verb Freq
Red John Jumps 2
Blue John Sleeps 1
Red Smith Jumps 1
Red Smith Walks 1

Is there a way to do this in R?

Upvotes: 0

Views: 24

Answers (2)

Ben Bolker
Ben Bolker

Reputation: 226077

Slightly clunkier than @G5W's, but:

## cross-tabulate
t1 <- with(dd,table(Adj,Name,Verb))
## convert to long format
res <- as.data.frame(t1)
## drop zeros
subset(res,Freq>0)

Upvotes: 1

G5W
G5W

Reputation: 37641

You can do this with aggregate. 

DAT = read.table(text="Adj Name Verb
Red John Jumps
Blue John Sleeps
Red John Jumps
Red Smith Jumps
Red Smith Walks",
header=TRUE)

aggregate(rep(1, nrow(DAT)), DAT, length)
   Adj  Name   Verb x
1  Red  John  Jumps 2
2  Red Smith  Jumps 1
3 Blue  John Sleeps 1
4  Red Smith  Walks 1

You could also use sum instead of length.

Upvotes: 3

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