This problem looks like this …
> df <- read.csv("data/no-header.csv")
> str(df)
'data.frame': 2 obs. of 2 variables:
$ X3: int 5 7
$ X4: int 6 8
> df
X3 X4
1 5 6
2 7 8
If you used read.csv()
, then this problem usually occurs if you have not included a header row on your CSV file. See how to construct an external CSV file in this FAQ.