[jira] [Created] (ARROW-11587) Implement a fixed-width file reader

["Stephanie Hazlitt (Jira)" <ji...@apache.org>]

Stephanie Hazlitt created ARROW-11587:
-----------------------------------------

             Summary: Implement a fixed-width file reader 
                 Key: ARROW-11587
                 URL: https://issues.apache.org/jira/browse/ARROW-11587
             Project: Apache Arrow
          Issue Type: Wish
          Components: R
            Reporter: Stephanie Hazlitt


Fixed-width files are a common data provisioning format for (very) large, administrative data files. We have been converting provisioned fwf files to `.parquet` and then leveraging `arrow::open_dataset()` with good success. However, we still run into RAM issues with the read-in step and are keen to try new approaches to this in-memory RAM issue (ideally without chunking files etc). 

A simple, example workflow looks like this:

```
sample_data <- "https://github.com/bcgov/dipr/raw/master/inst/extdata/starwars-fwf.dat.gz"

vroom::vroom_fwf(sample_data,
   col_positions = vroom::fwf_positions(
     c(1, 22, 25, 31),
     c(21, 24, 30, 35),
     c("name", "height", "mass", "has_hair")
     ),
     col_types = ("cnnl")
) %>%
    dplyr::group_by(has_hair) %>%
    arrow::write_dataset(path = "starwars_parquet",
     format = "parquet")
```

With an \{arrow} fixed-width reader, we could perhaps leverage `arrow::open_dataset(as_data_frame = FALSE)` directly on a large fwf file and then convert to partitioned `.parquet` files with arrow::write_dataset()?



--
This message was sent by Atlassian Jira
(v8.3.4#803005)