Subsetting columns not working correctly

Asked Apr 25 '16 at 17:49

Active Apr 25 '16 at 19:10

Viewed 69 times

I am running the following code:

library(data.table)
test <- fread("file location", colClasses = 'factor')
test <- test[1:100]
test[, c(1:5)]

I am trying to look at the first 100 observations and the first 5 columns, but when I run the second function the output is:

[1] 1 2 3 4 5

edited Apr 25 '16 at 19:10

David Arenburg

asked Apr 25 '16 at 17:49

ChrisYee90

Not sure what you are trying to achieve. Maybe show the structure? And then describe the expected output? – Ely Apr 25 '16 at 17:52
1

Or `head(test, 100)[, 1:5]` – Frank Apr 25 '16 at 17:53
here is my code that I used: – ChrisYee90 Apr 25 '16 at 17:57
test – ChrisYee90 Apr 25 '16 at 17:57
I am looking for an output of the first 100 observations and the first 5 columns. I believe it has something to do with fread – ChrisYee90 Apr 25 '16 at 17:58
4

`test[1:100, 1:5, with=FALSE]` – Pierre L Apr 25 '16 at 17:58
thanks! that was what i was looking for – ChrisYee90 Apr 25 '16 at 18:00
what does the with command do in that function? – ChrisYee90 Apr 25 '16 at 18:00
`fread` reads the data in and creates a `data.table` object. It behaves differently from data frames https://cran.r-project.org/web/packages/data.table/vignettes/datatable-intro.pdf – Pierre L Apr 25 '16 at 18:01
For reading a limited number of columns, see [this Q&A](http://stackoverflow.com/questions/5788117/only-read-limited-number-of-columns-in-r). – Jaap Apr 25 '16 at 18:31

0 Answers0