Adding frequency values with matching column name

Question

I have the following data frame:

Some background:

VAR1 is the Unique code, VAR2 is Person ID and FREQ is Total Count.

For example, Person 1 (P1) appears 29 times in code ABCD, they also appear 98 times in code EFGH. What I am trying to do, is make it so it looks like this:

Basically, I just want the total, so Person 1 has used a specific code (VAR1) 127 times. Person 2 has used a unique code 14 times

I'm unsure how to get this to work, as I'm just starting with R.

score 3 · Answer 1 · answered Apr 17 '17 at 21:12

3

In base R (where df is your data frame):

aggregate(.~var2, df, sum)[,c(1,3)]

#  var2 freq
#1   p1  127
#2   p2   14
#3   p3  135

answered Apr 17 '17 at 21:12

989

12,579
5
31
53

This works perfectly, thank you very much! – KieranLowe Apr 17 '17 at 21:17

score 2 · Answer 2 · answered Apr 17 '17 at 21:07

2

Using dplyr we can do this. Assuming df is the name of the data frame:

library("dplyr")    
df %>% group_by(VAR2) %>% summarise(count = sum(VAR3))

answered Apr 17 '17 at 21:07

svenhalvorson

1,090
8
21

This works perfectly too using dplyr! Thank you very much for your answer! – KieranLowe Apr 17 '17 at 21:18

score 0 · Answer 3 · answered Apr 17 '17 at 21:19

A data.table solution:

library(data.table)
dt[, list(freq = sum(Freq)), by = Var2]

#   Var2 freq
#1:   P1  127
#2:   P2   14
#3:   P3  135

Data:

dt <- fread("Var1 Var2 Freq
            ABCD P1 29
            ABCD P2 2
            ABCD P3 12
            EFGH P1 98
            EFGH P2 12
            EFGH P3 123")

Adding frequency values with matching column name

3 Answers3