I came accross this post on SO, where several solutions to sorting data.frames are presented. It must have been solved a million times, but here's a solution I like to use. It benefits from the fact that sort is an S3 generic.
sort.data.frame <- function(x, decreasing=FALSE, by=1, ... ){
f <- function(...) order(...,decreasing=decreasing)
i <- do.call(f,x[by])
x[i,,drop=FALSE]
}
It sorts on the first column by default, but you may use any vector of valid column indices. Here are some examples.
sort(iris, by="Sepal.Length")
sort(iris, by=c("Species","Sepal.Length"))
sort(iris, by=1:2)
sort(iris, by="Sepal.Length",decreasing=TRUE)
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very cool
How about the ability to sort different columns descending or ascending?
That's an interesting question. This function depends on 'order', and that doesn't have such facilities.
This function is quite pretty. I want to know which sorting algorithm is used in this function. How to write a function a function to insert into a sorted data frame.
R uses an implementation of quicksort, see ?sort.
Regarding insertion, a data.frame is not a database-like object. You can only append two compatible data.frames with rbind(). If you need a lot of such operations,
have a look at the data.table package, or check out RSQLite.