[GitHub] [arrow] csgillespie opened a new issue, #37762: Column names that are empty strings

["csgillespie (via GitHub)" <gi...@apache.org>]

csgillespie opened a new issue, #37762:
URL: https://github.com/apache/arrow/issues/37762

   ### Describe the bug, including details regarding any error messages, version, and platform.
   
   The following fails
   ```
   library(arrow)
   library(dplyr)
   write.csv(sleep, "sleep.csv", row.names = TRUE)
   open_dataset("sleep.csv", format = "csv") |>
     mutate(group = group + 1) |>
     collect()
   # Error in env_bind0(env, data) : attempt to use zero-length variable name
   ```
   This is due to the first column having no column name.
   ```
   open_dataset("sleep.csv", format = "csv") |>
      head() |>
      collect()
   # A tibble: 6 × 4
        `` extra group    ID
     <int> <dbl> <int> <int>
   1     1   0.7     1     1
   2     2  -1.6     1     2
   ```
   
   ### Component(s)
   
   R


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[GitHub] [arrow] thisisnic commented on issue #37762: [R] Column names that are empty strings

["thisisnic (via GitHub)" <gi...@apache.org>]

thisisnic commented on issue #37762:
URL: https://github.com/apache/arrow/issues/37762#issuecomment-1723225540

   Thanks for reporting this @csgillespie! 


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[GitHub] [arrow] nealrichardson commented on issue #37762: [R] Column names that are empty strings

["nealrichardson (via GitHub)" <gi...@apache.org>]

nealrichardson commented on issue #37762:
URL: https://github.com/apache/arrow/issues/37762#issuecomment-1724002604

   FWIW if you use `read.csv()` or `readr::read_csv()` on that file, both will fill in a non-empty name for the first column (`"X"` and `"...1"`, respectively). Not saying we should copy that, but that would be one reason they would not error if you tried the same on a data.frame version of this.
   
   Not sure where exactly we should check this since it's technically not invalid in Arrow. And unfortunately it's not trivial to fix either once you've read it in. `dplyr::rename()` doesn't seem to let you rename an empty name. `names<-.Dataset` is not implemented, though it could be. You can do `names(ds$schema)[1] <- "not_empty"` and that does work, though clearly suboptimal.


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