CODEWITHSUNDEEP
rsumaggregate
Thirst for Knowledge
Thirst for Knowledge

Reputation: 1628

Using aggregate to sum a numerical variable, according to categorical data in another character column (R)

I've found similar queries listed on here, but none of them have been able to work for me. I have binary data listed in a data frame which I want to aggregate according to another variable. For example. 

Data.frame (A & B are columns)
A   B   
1   23
0   7
0   23
0   7
1   4

I've tried the below (which worked when finding the mean) and get the following error message:

aggregate( A~B, data.frame, sum)

Error in FUN(X[[1L]], ...) : invalid 'type' (character) of argument

Ideally I would like an output which gives 23 = 1, 7 = 0, 4 = 1

Can anyone help me please?

Thanks in advance!

Upvotes: 0

Views: 8357

Answers (2)

Beasterfield
Beasterfield

Reputation: 7123

What did you call exactly? What is the str of your data.frame?

mdf <- data.frame( A = c(1,0,0,0,1), B = c(23, 7 ,23, 7,4)
aggregate( A ~ B, mdf, sum )

gives

   B A
1  4 1
2  7 0
3 23 1

EDIT:

So just in case your problem is, that your column A is not numeric you can fix this by

mdf$A <- as.numeric( as.character( mdf$A ) )

Upvotes: 0

SlowLearner
SlowLearner

Reputation: 8017

Many ways to do this, but for a start:

library(plyr)
foo <- data.frame(A = c(1, 0, 0, 0, 1),
                  B = c(23, 7, 23, 7, 4))

ddply(foo, .(B), summarise, sum = sum(A))

gives:

> ddply(foo, .(B), summarise, sum = sum(A))
   B sum
1  4   1
2  7   0
3 23   1
>

Upvotes: 1

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