How to sum a variable by group
I have a data frame with two columns. First column contains categories such as "First", "Second", "Third", and the second column has numbers that represent the number of times I saw the specific groups from "Category".
For example:
Category Frequency
First 10
First 15
First 5
Second 2
Third 14
Third 20
Second 3
I want to sort the data by Category and sum all the Frequencies:
Category Frequency
First 30
Second 5
Third 34
How would I do this in R?