CODEWITHSUNDEEP
rdataframesumaggregateaggregate-functions
user6780841
user6780841

Reputation: 33

Create df aggregating from multiple rows into single row in R

I'm working with an events dataset and need help in creating a new df by summing a specific variable based on certain conditions.

For example, lets say I had a dataset of all cars sold in a county with the name of the dealership, the month the car was sold, the year the car was sold, and the number of cars sold for the past n years. I want to create a new df where each row would present the number of cars sold by a particular dealership at the year level.

In other words, I want to go from something like this: 

Dealership   Month    Year    # of Cars
Bobs         April    2016    12
Toms         March    2016    8
Bobs         July     2016    20
Toms         June     2016    4
...

To

Dealership   Month    Year    # of Cars
Bobs         ?        2016    32
Toms         ?        2016    12
...

I'm not sure if that will give me an error because the month data (or other columns in a bigger dataset) will be different. I just don't need that information.

Can anyone help? Many thanks.

Upvotes: 0

Views: 217

Answers (1)

Jonathan Carroll
Jonathan Carroll

Reputation: 3947

We can only do so much without a reproducible example, but this is probably covered by dplyr

library(dplyr)
yourdata %>% group_by(Dealership, Year) %>% summarise(Ncars = sum(`# of Cars`))

Upvotes: 1

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