5. Advanced Data Structures

Sometimes data require more complex storage than simple vectors and thankfully R provides a host of data structures. The most common are the data.frame, matrix and list, followed by the array. Of these, the data.frame will be most familiar to anyone who has used a spreadsheet, the matrix to people familiar with matrix math and the list to programmers.

5.1 data.frames

Perhaps one of the most useful features of R is the data.frame. It is one of the most often cited reasons for R’s ease of use.

On the surface a data.frame is just like an Excel spreadsheet in that it has columns and rows. In statistical terms, each column is a variable and each row is an observation.

In terms of how R organizes data.frames, each column ...

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