Question

I have two data frames: A and B of the same number of columns names and content. Data frame B is the subset of A. I want to get A without B. I have tried different functions like setdiff, duplicated, which and others. None of them worked for me, perhaps I didn’t use them correctly. Any help is appreciated.

Answer 1

You could use merge e.g.:

df1 <- data.frame(col1=c('A','B','C','D','E'),col2=1:5,col3=11:15)
subset <- df1[c(2,4),]

subset$EXTRACOL <- 1 # use a column name that is not present among 
                     # the original data.frame columns
merged <- merge(df1,subset,all=TRUE)

dfdifference <- merged[is.na(merged$EXTRACOL),]
dfdifference$EXTRACOL <- NULL

-----------------------------------------
> df1:
  col1 col2 col3
1    A    1   11
2    B    2   12
3    C    3   13
4    D    4   14
5    E    5   15

> subset:
  col1 col2 col3
2    B    2   12
4    D    4   14

> dfdifference:
  col1 col2 col3
1    A    1   11
3    C    3   13
5    E    5   15