- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to find the number of columns where all row values are equal in R data frame?
To find the number of columns where all row values are equal in R data frame, we can follow the below steps −
First of all, create a data frame.
Then, use sum function along with length and apply function to find the number of columns where all row values are equal.
Example 1
Create the data frame
Let’s create a data frame as shown below −
x<-rpois(25,1) y<-rpois(25,1) z<-rpois(25,1) df<-data.frame(x,y,z) df
Output
On executing, the above script generates the below output(this output will vary on your system due to randomization) −
x y z 1 2 1 5 2 1 0 0 3 0 1 1 4 2 0 2 5 0 1 3 6 1 1 1 7 0 0 2 8 1 1 2 9 2 0 0 10 2 0 0 11 2 0 0 12 0 1 0 13 3 0 1 14 1 2 0 15 4 1 0 16 0 4 0 17 0 1 1 18 0 0 1 19 5 0 0 20 0 1 1 21 0 1 1 22 1 1 1 23 1 0 2 24 1 0 2 25 1 1 1
Find the number of columns where all row values are equal
Using sum function along with length and apply function to find the number of columns where all row values are equal in data frame df1 −
x<-rpois(25,1) y<-rpois(25,1) z<-rpois(25,1) df<-data.frame(x,y,z) sum(apply(df, 1, function(x) length(unique(x))==1))
Output
[1] 5
Example 2
Create the data frame
Let’s create a data frame as shown below −
v1<-round(rnorm(25),0) v2<-round(rnorm(25),0) dat<-data.frame(v1,v2) dat
Output
On executing, the above script generates the below output(this output will vary on your system due to randomization) −
v1 v2 1 -1 -1 2 -1 1 3 3 0 4 0 0 5 0 0 6 0 0 7 0 -1 8 1 0 9 -1 -1 10 1 2 11 1 0 12 -1 1 13 1 1 14 -1 -1 15 -1 0 16 0 1 17 -1 2 18 1 -1 19 2 1 20 0 -1 21 0 -1 22 -1 -1 23 0 -2 24 0 0 25 3 0
Find the number of columns where all row values are equal
Using sum function along with length and apply function to find the number of columns where all row values are equal in data frame df2 −
v1<-round(rnorm(25),0) v2<-round(rnorm(25),0) dat<-data.frame(v1,v2) sum(apply(dat, 1, function(x) length(unique(x))==1))
Output
[1] 6