Add specific columns from one dataframe to another based on matched cases

Question

I have two dataframes and I want to add two columns AGE and IQ from the data2 dataframe to the data1 dataframe only for matching ID. Here is an example of the two dataframes:

    data1= structure(list(ID = c(1L, 2L, 3L, 4L, 5L), CONDITION = structure(c(1L, 1L, 1L, 2L, 2L), .Label=c("ANX","ADHD"), class = "factor")), class = "data.frame", row.names = c(NA, -5L))

    data2= structure(list(ID = c(1L, 2L, 3L, 4L, 5L, 6L, 7L), CONDITION = structure(c(1L, 1L, 1L, 2L, 2L, 3L, 3L), .Label=c("ANX","ADHD", "COM"), class = "factor"), AGE = c(7L, 8L, 8L, 9L, 9L, 10L, 11L), IQ =c(78L, 83L, 116L, 90L, 80L, 85L, 87L)), .Names= c("ID", "CONDITION", "AGE", "IQ"), class = "data.frame", row.names = c(NA, -7L))

So far i have tried something like:

    merge(data1, data2[, c("AGE", "IQ")], by= "ID")

Any help will be much appreciated! Thanks in advance.

You need common columns. In `data2`, you skipped 'ID'. It would be `merge(data1, data2[, c("AGE", "IQ","ID")], by= "ID")` — akrun, Nov 28 '17 at 17:41
@akrun, thanks, did it! I was silly and blind for some time now. Thanks a lot!:) — Ath, Nov 28 '17 at 17:49

score -1 · Answer 1 · answered Nov 28 '17 at 17:45

-1

data1$AGE <- data2$AGE[match(data1$ID, data2$ID)]
data1$IQ <- data2$IQ[match(data1$ID, data2$ID)]

answered Nov 28 '17 at 17:45

Mouad_Seridi

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Add specific columns from one dataframe to another based on matched cases

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