[R] why data.frame, mutate package and not lists

[Marc Schwartz]

> On Sep 14, 2016, at 8:01 AM, Alaios via R-help <r-help at r-project.org> wrote:
> 
> Hi all,I have seen data.frames and operations from the mutate package getting really popular. In the last years I have been using extensively lists, is there any reason to not use lists and use other data types for data manipulation and storage?
> Any article that describe their differences? I would like to thank you for your replyRegardsAlex

Hi,

Presuming that you are referring to the mutate() **function**, which is in the dplyr package on CRAN, that package provides a variety of functions to manipulate data in R.

Data frames **are** lists with a data.frame class attribute, but with the proviso that each column in the data frame, which is a list element, has the same length, but like a list, may have different data types (e.g. character, numeric, etc.). 

Thus, a data frame is effectively a rectangular data structure, conceptually in the same manner as an Excel worksheet.

A list, which is a more generic data structure, can contain list elements of variable lengths and data types. 

You might want to begin by reviewing:

  https://cran.r-project.org/doc/manuals/r-release/R-intro.html#Lists-and-data-frames

which is a section on lists and data frames in the Introduction To R Manual.

It would be surprising, to me at least, that you have been using R for several years and have not come across data frames, since they are used in many typical operations, including regression models and the like.

Regards,

Marc Schwartz