Group By Using Looping

Question

I have a data set where i need to obtain sum of various variables by grouping it by a variable in R. The data set is as follows:

V1 V2 V3 V4
1  2   3 a
5  6   7 a
3  2   3 b
5  6   7 b

I want the output in the form:

V1 V2 V3 V4
6  8  10  a
8  8  10  b

I want to use a loop for doing this. It will be great if someone can help

ArunK · Answer 1 · 2016-06-02T07:46:03.667

0

you can use dplyr library do that

library("dplyr")
df <- data.frame(V1 = c(1,5,3,5), V2 = c(2,6,2,6), V3 = c(3,7,3,7), V4 = c("a","a","b","b")
res_df <- df %>% group_by(V4) %>% summarise(V1=sum(V1),V2=sum(V2),V3=sum(V3))

edited Jun 02 '16 at 07:46

answered Jun 02 '16 at 07:25

ArunK

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1

You should use `summarise_each(funs(sum))` here. – Tutuchan Jun 02 '16 at 07:37
I tried the `summarise_each`, however, I get the following error `error in UseMethod("group_by_")` – ArunK Jun 02 '16 at 07:46

Group By Using Looping

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