CODEWITHSUNDEEP
r
Young Grasshopper
Young Grasshopper

Reputation: 47

Sum up Specific Rows Based on Name in R and Create New Column

This is probably an easy question to answer, but I haven't been able to find a solution.

Assume I have the following dataframe:

    Name    Value
    Bob     100
    Bob     500
    Jim     50
    Rach    300
    Rach    300
    Rach    300

I need to create a new column that adds the value for each person. The end result should look something like this:

    Name     Value      Sum
    Bob      100        600
    Bob      500        600
    Jim      50         50
    Rach     300        900
    Rach     300        900
    Rach     300        900

Thank you in advance for any help with this problem.

Upvotes: 0

Views: 1742

Answers (2)

Erich Studerus
Erich Studerus

Reputation: 557

Another simple solution is:

dat <- data.frame(Name = c('Bob', 'Bob', 'Jim', 'Rach', 'Rach', 'Rach'),
           Value = c(100, 500, 50, 300, 300, 300))
transform(dat, sum_name = ave(Value, Name, FUN = sum))

Upvotes: 3

Paul Hiemstra
Paul Hiemstra

Reputation: 60924

plyr is your friend:

library(plyr)
ddply(dat, .(Name), transform, sum_name = sum(Value))
  Name Value sum_name
1  Bob   100      600
2  Bob   500      600
3  Jim    50       50
4 Rach   300      900
5 Rach   300      900
6 Rach   300      900

Assuming your data is in the data.frame dat. For other possible solutions take a look at the data.table package and the R base functions aggregate, by, split.

Upvotes: 1

Related Questions