Some other data types

Strings and numbers are just two of the data types R can work with. What else? Well, there are lists:

> list( "This", "list", "has", 5, "entries" )

As you can see, a list is just a list of things, and the things can be of different types.

There are also vector types, which we've seen already - they are a kind of list where all the entries have the same type. The c() (for 'concatenate') function can be used to stick things together into a vector:

> c( "This", "vector", "has", "5", "entries" )

You can also create matrixes:

> matrix( 1:6, nrow = 2 )

Question

Did this matrix get filled row-wise (along rows) or column-wise with the numbers 1 to 6?

And multidimensional arrays - for example here's a 25 x 2 x 2 array:

> array( 1:40, dim = c( 10, 2, 2 ))

There's also another very useful type, the data frame, which is often used to store scientific data. We'll come back to it a bit later.