I am interested in calculate the medians of a data.frame. I found two approaches to do it: 1) with
tapply and 2) with
For many reasons, I am more interested in the "
aggregate approach". However, since it gives me a data.frame and I need an array, I need to transform it. I found that there is a function that tries to do this (
simply2array) but it doesn’t give me exactly an array.
Here is my example:
When I try to calculate the median with tapply, it gives me an array
df_median2 <- tapply(mtcars$mpg, mtcars$gear, median) > class(df_median2)  "array"
However, I need to use
aggregate, which gives me a dataframe. In the following code, I tried to change it as much as I can to transform it into an array (without success)
df_median <- aggregate(mtcars$mpg ~ mtcars$gear, FUN=median) df_median <- as.data.frame(t(df_median)) names(df_median) <- df_median[1,] df_median <- df_median[-1,] rownames(df_median) <- "mpg" my_array <- simplify2array(df_median) > class(my_array)  "numeric"
So… my question is, do you know if it is possible to convert a data.frame into an array in R?
Thanks very much in advance
The simplest way is to use this:
If you want to include
colnames you can use the
dimnames = parameter in
If you also want to include the
rownames you have to provide both the
dimnames = and
dim = parameter in