Matching two columns in a dataframe - R

Question

I want to use R to match the content of my data frame it has two columns which look like:

1B-73066    1C-80140
1B-73068    1C-80154
1B-73070    1D-21647
1B-73076    1D-21648
1C-1095    1B-73066
1C-1096    1B-73068
1C-14080    1B-73070
1C-1582    1B-73076

I want to sort the two columns so like matches like, and any non-match is printed also

1B-73066    1B-73066
1B-73068    1B-73068
1B-73070    1B-73070
1B-73076    1B-73076
1C-1095 1C-1095
1C-80140
1C-80154

Thanks

Answer 1

This seems to do what you ask for, though I'm confused by your example:

df <- read.table(text="1B-73066    1C-80140
+ 1B-73068    1C-80154
+ 1B-73070    1D-21647
+ 1B-73076    1D-21648
+ 1C-1095    1B-73066
+ 1C-1096    1B-73068
+ 1C-14080    1B-73070
+ 1C-1582    1B-73076",stringsAsFactors = FALSE)
> 
> names(df) <- c("A","B")
> df2 <- data.frame(
+   A = c(intersect(df$A,df$B),setdiff(df$A,df$B),rep("",length(setdiff(df$B,df$A)))),
+   B = c(intersect(df$A,df$B),rep("",length(setdiff(df$A,df$B))),setdiff(df$B,df$A)))

# > df2
# A        B
# 1  1B-73066 1B-73066
# 2  1B-73068 1B-73068
# 3  1B-73070 1B-73070
# 4  1B-73076 1B-73076
# 5   1C-1095         
# 6   1C-1096         
# 7  1C-14080         
# 8   1C-1582         
# 9           1C-80140
# 10          1C-80154
# 11          1D-21647
# 12          1D-21648