Sum rows under conditions in R

Question

I would like to sum rows of two columns based on a condition of a variable "country". The output should give a new column that has only values for specified countries and NA's for the rest. For instance:

P  R  Country Total
1  1  IT       2
2  2  DE       4
3  3  FR       NA
4  4  FR       NA
5  5  DE       10
6  6  IT       12

score 2 · Accepted Answer · answered Mar 14 '17 at 22:50

2

You can use ifelse for this:

your_data$Total = with(your_data, ifelse(Country %in% c("IT", "DE"), P + R, NA))

answered Mar 14 '17 at 22:50

Gregor Thomas

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Worked perfectly. Thank you! – Laura Mar 14 '17 at 22:59
With other variables, it gives me NA's. I tried `as.numeric` but it did not help. Do you know what it might be? – Laura Mar 14 '17 at 23:14
2

Nope. Ask a new question [and share some data reproducibly as described here.](http://stackoverflow.com/q/5963269/903061) – Gregor Thomas Mar 14 '17 at 23:18

Sum rows under conditions in R

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