What are R levels?

Question

I am trying to read a csv file with R. I can read the file but I have levels when I call a variable. What are these levels and how can I remove them? The file can be downloa

Answer 1

The presence of levels for your variable HomeTeam indicates that it is a factor (with 20 levels). You can specify StringAsFactors=FALSE argument in the read.csv function to remove it.

Answer 2

When you use ?read.csv to read a file, the argument stringsAsFactors is set by default to TRUE, you just need to set it to false to not get this result. This should work:

data = read.csv("Documents/bet/I1.csv", sep=",", stringsAsFactors=FALSE)

Under the default, columns (variables) in the file that contain strings are assumed to be factors. A factor is a categorical variable that can take only one of a fixed, finite set of possibilities. Those possible categories are the levels. You can read about factors in the R Intro manual here, and this is another tutorial.

In addition, since you are using read.csv, adding the sep="," is redundant. It doesn't harm anything, but the comma is taken as the separator by default.