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How to compare two columns in an R data frame for an exact match?
Sometimes analysis requires the user to check if values in two columns of an R data frame are exactly the same or not, this is helpful to analyze very large data frames if we suspect the comparative values in two columns. This can be easily done with the help of ifelse function.
Example
Consider the below data frame −
x1<-sample(c("Spring","Winter","Autumn","Summer"),20,replace=TRUE)
y1<-sample(c("Spring","Winter","Autumn","Summer"),20,replace=TRUE)
df1<-data.frame(x1,y1)
df1Output
x1 y1 1 Spring Autumn 2 Winter Winter 3 Summer Summer 4 Autumn Autumn 5 Summer Autumn 6 Autumn Autumn 7 Summer Winter 8 Spring Spring 9 Summer Spring 10 Winter Winter 11 Autumn Summer 12 Autumn Summer 13 Spring Winter 14 Spring Winter 15 Spring Spring 16 Summer Autumn 17 Spring Winter 18 Winter Summer 19 Summer Spring 20 Spring Autumn
Determining whether each value in x1 and y1 are same or not −
Example
ifelse(df1$x1==df1$y1,"Yes","No")
Output
[1] "No" "Yes" "Yes" "Yes" "No" "Yes" "No" "Yes" "No" "Yes" "No" "No" [13] "No" "No" "Yes" "No" "No" "No" "No" "No"
Example
x2<-sample(c("Male","Female"),20,replace=TRUE)
y2<-sample(c("Male","Female"),20,replace=TRUE)
df2<-data.frame(x2,y2)
df2Output
x2 y2 1 Male Female 2 Female Male 3 Female Female 4 Male Male 5 Female Female 6 Male Female 7 Female Female 8 Male Male 9 Male Female 10 Female Female 11 Female Female 12 Male Female 13 Male Male 14 Female Male 15 Male Male 16 Female Female 17 Male Male 18 Female Female 19 Male Female 20 Male Female
Determining whether each value in x2 and y2 are the same or not −
Example
> ifelse(df2$x2==df2$y2,"Yes","No")
Output
[1] "No" "No" "Yes" "Yes" "Yes" "No" "Yes" "Yes" "No" "Yes" "Yes" "No" [13] "Yes" "No" "Yes" "Yes" "Yes" "Yes" "No" "No"
Updated on: 07-Dec-2020
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