Checking for identical columns in a data frame in R

Question

Suppose you have a data frame called data with two identical columns:

A B 1 1 2 2 3 3 4 4 

How can I check if these two columns are identical and return one logical value to indicate it? A very basic pseudocode is:

if(data$A == data$B) {    print("Column A and B are identical") } 

I have been messing around with this for a bit and haven't found a way to do it that doesn't seem unnecessarily convoluted. Thanks.

Answer 1

You could use identical

identical(DT[['A']],DT[['B']]) 

Answer 2

You could use all():

> data <- data.frame(A=c(1,2,3,4), B=c(1,2,3,4)) > all(data$A == data$B) [1] TRUE