R - Merge data, save failed output

Question

I've merged some data, and it works great. But I'd like to know what data that's left out, i.e. data that didn't "find" matching data and was thus discarded. Is there a way to do something like this:

not_merged<-!merge(df1,df2)

The code above is pseudo code. The code below isn't.

df1 = data.frame(CustomerId = c(1:6), Product = c(rep("Toaster", 3), rep("Radio", 3)))
df2 = data.frame(CustomerId = c(2, 4, 6), State = c(rep("Alabama", 2), rep("Ohio", 1)))
merged<-merge(df1,df2)

score 2 · Accepted Answer · answered Nov 05 '15 at 19:37

2

You can use an anti_join from the dplyr package:

library(dplyr)

anti_join(df1, df2)

answered Nov 05 '15 at 19:37

jeremycg

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Obligatory data.table analogue: `setDT(df1)[!df2, on="CustomerId"]` – Frank Nov 05 '15 at 19:40
Thanks for your help! – Isak Nov 05 '15 at 21:12

R - Merge data, save failed output

1 Answers1