How to count the number of occurrences of all unique values in an R data frame?
A data frame in R can have infinite number of unique values and it can also contain many repeated values. Therefore, finding the number of all unique values in the data frame can help us to understand the diversity in the data but this most done in situations where we expect to have repeated elements otherwise it would not make sense. To count the number of occurrences of all unique values, we can use table function along with the unlist as shown in the below examples.
Consider the below data frame −
Example
Live Demo
x1<-sample(LETTERS[1:5],20,replace=TRUE)
x2<-sample(LETTERS[1:5],20,replace=TRUE)
x3<-sample(LETTERS[1:5],20,replace=TRUE)
x4<-sample(LETTERS[1:5],20,replace=TRUE)
x5<-sample(LETTERS[1:5],20,replace=TRUE)
df1<-data.frame(x1,x2,x3,x4,x5)
df1
Output
x1 x2 x3 x4 x5
1 B E D E E
2 E A C E E
3 C A D A D
4 C C A D C
5 D D A C B
6 C C E E B
7 B B C B A
8 A E B C B
9 E D E B E
10 C B A C A
11 C C C B D
12 A B C A A
13 C D D C C
14 E C E D C
15 A A B D E
16 E D E A E
17 C C A D E
18 C C E C D
19 B B A E B
20 D B D A B
Finding the number of unique values in the data frame df1 −
Example
table(unlist(df1))
Output
A B C D E
18 27 22 17 16
Let’s have a look at another example −
Example
Live Demo
y1<-sample(0:2,20,replace=TRUE)
y2<-sample(0:2,20,replace=TRUE)
y3<-sample(0:2,20,replace=TRUE)
y4<-sample(0:2,20,replace=TRUE)
df2<-data.frame(y1,y2,y3,y4)
df2
Output
y1 y2 y3 y4
1 0 2 1 2
2 0 0 1 1
3 1 1 2 1
4 2 2 0 0
5 1 0 2 1
6 0 2 2 0
7 0 0 1 1
8 0 2 0 1
9 2 2 2 2
10 1 0 2 0
11 0 1 1 2
12 2 2 2 1
13 0 1 1 0
14 2 2 1 2
15 2 2 0 0
16 2 2 1 1
17 1 2 2 2
18 2 1 0 2
19 1 0 2 0
20 1 2 0 2
Finding the number of unique values in the data frame df2 −
Example
table(unlist(df2))
Output
0 1 2
32 26 22
Published on 19-Oct-2020 13:55:59
Data Structure
Networking
RDBMS
Operating System
Java
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP