CODEWITHSUNDEEP
rtidyverser-haven
Jonathan Nolan
Jonathan Nolan

Reputation: 145

read_sas cols_only supress error Evaluation error: Column 2 must be named

I have a long list of very large SAS files. I want to import them using read_sas. To increase speed and reduce memory usage I want to only import the columns I am interested in using cols_only.

The trouble is, I have a long list of possible column names - but not every column is in my dataset. If I pass the full list to cols_only, I get the error: 

Evaluation error: Column 2 must be named.

Is there a way to suppress this error, and encourage read_sas to do its best to import whatever variables it can from the list I have passed?

Upvotes: 2

Views: 226

Answers (1)

Mikko Marttila
Mikko Marttila

Reputation: 11878

As @Andrew mentions in their comment, with haven >= 2.2.0 you can use the new col_select argument for this. To select columns that may not exist, use the helper one_of():

library(haven)
library(tidyselect)

f <- tempfile()
write_sas(mtcars, f)

my_cols <- c("mpg", "i-don't-exist")
read_sas(f, col_select = one_of(my_cols))
#> Warning: Unknown columns: `i-don't-exist`
#> # A tibble: 32 x 1
#>      mpg
#>    <dbl>
#>  1  21  
#>  2  21  
#>  3  22.8
#>  4  21.4
#>  5  18.7
#>  6  18.1
#>  7  14.3
#>  8  24.4
#>  9  22.8
#> 10  19.2
#> # ... with 22 more rows

Upvotes: 4

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