How to calculate median of profits for a particular country

Question

Hello folks, I am new to R and I am trying to compute median profit for a particular country in a data frame.I tried below one but it doesn\'t work for me.

Answer 1

David already answered your initial question and showed you one way to find the median for multiple countries. Here is another way:

You can split the data.frame by country to create a list of data.frames for each country

L <- split(Forbes2000, Forbes2000$country)

Then, you can apply a function to each component of the list with either lapply or sapply. (sapply simplifies the result to an array, whereas lapply returns a list)

sapply(L, function(x) {
    median(x$sales)
})

or, in one line

sapply(split(Forbes2000, Forbes2000$country), function(x) median(x$sales))