Making and creating rankings is one of mankind's favorite affairs. These rankings can be useful (best universities in the world), entertaining (most influential movie stars) or pointless (best 007 look-a-like).
In data analysis you can sort your data according to a certain variable in the data set. In R, this is done with the help of the function order().
order() is a function that gives you the ranked position of each element when it is applied on a variable, such as a vector for example:
> a <- c(100, 10, 1000)
> order(a)
[1] 2 1 3
10, which is the second element in a, is the smallest element, so 2 comes first in the output of order(a). 100, which is the first element in a is the second smallest element, so 1 comes second in the output of order(a).
This means we can use the output of order(a) to reshuffle a:
> a[order(a)]
[1] 10 100 1000
Experiment with the order() function in the console. Click 'Submit Answer' when you are ready to continue.
load(url("http://s3.amazonaws.com/assets.datacamp.com/course/intro_to_r/planets.RData"))
# Play around with the order function in the console
# Play around with the order function in the console
success_msg("Great! Now let's use the `order()` function to sort your data frame!")
Just play with the order() function in the console!