head() function failing

Question

I want to use the head() function to have an overview of the data set but it doesn't work.

> library(haven)
> corona <- read_sav("Corona_FB/Corona_FB/TRR265_CoronaFB_16-12-2020.sav")
> View(corona)
> head(corona)

Error in is.character(subclass) : argument "subclass" is missing, with no default

> head(corona,n=3)

Error in is.character(subclass) : argument "subclass" is missing, with no default

unfortunately we almost certainly can't answer this question without more information. At the **very** least, what is `class(corona)`? Can you please post a [mcve] ? — Ben Bolker, Dec 17 '20 at 21:43
Are you sure you didn't load any other library? Type `head` into console (without brackets) to see from which namespace is the function — Jan Kislinger, Dec 17 '20 at 21:45
I imagine @JanKislinger has hit the answer. Try running just the couple of lines of code in a totally fresh R session and see if you get the same issue. — thelatemail, Dec 17 '20 at 21:48
@BenBolker: > class(corona) [1] "tbl_df" "tbl" "data.frame" I tried as.data.frame for "corona" and it works but I dont know why. Do you happen to know why? — Đỗ Ngọc Trâm, Dec 17 '20 at 22:25

score 1 · Answer 1 · answered Dec 18 '20 at 01:39

Since your object is a tibble (class "tbl_df" "tbl" "data.frame"), which is a very widely used object class, the problem is probably with the head() function/method. In a clean R session (i.e., no other objects in the workspace), with only the haven and tidyverse packages loaded, this works fine:

library(tidyverse)
library(haven)
dd <- tibble(x=1:5,y=2:6)
head(dd)

There is about a 99% chance that you have somehow gotten a weird version of head defined (a 1% chance that your data object (corona) is weird). To be sure that it's not your data object, we would need a reproducible example, i.e. you would have to give us access to your data file or to your data object dumped with save() or dput()).

If find("head") returns anything other than "package:utils", then you do indeed have a different head() function masking the base-R version. You can make sure you are using the base-R version by using utils::head() instead of head(). If the weird version of head() is in your global workspace (i.e. find("head") returns ".GlobalEnv") then you may want to get rid of it by saying rm("head").

Alternatively, as suggested in the comments, you could see if your code works in a clean R session, i.e. one where you have no other packages loaded or objects defined in your workspace. (Restarting R usually works, but you need to make sure that you're not restoring a workspace from a previous R session.)

In the meantime, if you want an "overview" of your data set, you could also try summary() or str().

head() function failing

1 Answers1