Inner Join with conditions in R

Question

I want to do inner join with the condition that it should give me subtraction of 2 columns.

df1 = data.frame(Term = c(\"T1\",\"T2\",\"T3\"), Sec = c(\         


        

Answer 1

Using data.tables binary join you can modify columns while joining. nomatch = 0L makes sure that you are doing an inner join

library(data.table)
setkey(setDT(df2), Sec)
setkey(setDT(df1), Sec)[df2, .(Term, Sec, Value = abs(Value - i.Value)), nomatch = 0L]
#    Term Sec Value
# 1:   T1  s1    30
# 2:   T2  s2    20
# 3:   T3  s3    10