Teja - 5 months ago 38

R Question

I am trying to get the top 'n' companies from a data frame.Here is my code below.

`data("Forbes2000", package = "HSAUR")`

sort(Forbes2000$profits,decreasing=TRUE)

Now I would like to get the top 50 observations from this sorted vector.

Answer

`head`

and `tail`

are really useful functions!

```
head(sort(Forbes2000$profits,decreasing=TRUE), n = 50)
```

If you want the first 50 rows of the data.frame, then you can use the `arrange`

function from `plyr`

to sort the `data.frame`

and then use `head`

```
library(plyr)
head(arrange(Forbes2000,desc(profits)), n = 50)
```

Notice that I wrapped `profits`

in a call to `desc`

which means it will sort in decreasing order.

To work without plyr

```
head(Forbes2000[order(Forbes2000$profits, decreasing= T),], n = 50)
```