Insert new observation by group that is a sum(or weighted sum) in r

Question

i am still new to R and many things are still hard to execute. The community here has been very helpful! I have yet another problem. 1. Creating a new observation for each group that would be the sum(or weighted sum) of certain variables 2. Creating a weighted sum for a variable that has sometimes NA in it

My dataset:

    df = structure(list(ID = c(1L, 1L, 2L, 2L, 3L, 3L, 4L, 4L, 4L), ID_name = c("AA", "AA", "BB", "BB", "CC","CC", "DD","DD","DD"),
    Volume = c(10L, 20L, 30L, 50L, 50L, 40L, 20L, 
    30L, 10L), Score= c(0.1L, 0.3L, 0.5L, NA, 0.6L, NA, 
    0.6L, 0.2L, 0.6L)).Names = c("ID", "ID_name","Volume","Score"), class = "data.frame", row.names = c(NA, -9L))

I want to 1.Create a new observation for each unique ID, that is ID 1, ID 2, ID 3, and ID 4

2. Have these new observations be as follows: ID ID_name Volume Score (weighted average) 1 AA 30 (that is 10+20) (10*0.1+0.3*20)/(10+20) = 0.23 2 BB 80 (30+50) (30*0.5)/30=0.5 (NA row is ignored in score calculation) 3 CC 90 (50+40) (60*0.6)/60=0.6 (NA row is ignored in score calculation) 4 DD 60 (20+30+10) (20*0.6+30*0.2+10*0.6)/60=0.4

I tried mutate function but that doesn't seem to work. Any leads would be very appreciated. Thanks

There's something wrong with the `dput` you provide. – AntoniosK Nov 09 '17 at 15:01 — AntoniosK, Nov 09 '17 at 15:01

score 0 · Accepted Answer · answered Nov 09 '17 at 14:58

library(dplyr)

df = data.frame(ID = c(1L, 1L, 2L, 2L, 3L, 3L, 4L, 4L, 4L), 
                ID_name = c("AA", "AA", "BB", "BB", "CC", "CC", "DD", "DD", "DD"), 
                Volume = c(10L, 20L, 30L, 50L, 50L, 40L, 20L, 30L, 10L), 
                Score = c(0.1, 0.3, 0.5, NA, 0.6, NA, 0.6, 0.2, 0.6))


df %>%
  mutate(HasScore = ifelse(is.na(Score), 0, 1)) %>%
  group_by(ID, ID_name) %>%
  summarise(WA = sum(Volume*Score, na.rm = T)/sum(Volume*HasScore),
            Volume = sum(Volume)) %>%
  ungroup()

# # A tibble: 4 x 4
#      ID ID_name        WA Volume
#   <int>  <fctr>     <dbl>  <int>
# 1     1      AA 0.2333333     30
# 2     2      BB 0.5000000     80
# 3     3      CC 0.6000000     90
# 4     4      DD 0.4000000     60

AntoniosK, the elegant lines of codes worked like magic! Thank you so so so much!!!!!! — T.Z, Nov 09 '17 at 16:11

Insert new observation by group that is a sum(or weighted sum) in r

1 Answers1