Split Metadata Fields Out of a File Name

Many measurement archives encode a recording's design cells in its file name, e.g. ID052_K_K_KG00_MS.asc for subject ID052, saddle K, pad K, weight KG00, mode MS. This splits such a base name into a one-row tibble of named fields.

Usage

pr_meta_from_filename(
  path,
  fields,
  sep = "_",
  on_fail = c("skip", "error", "na")
)

Arguments

path

Character scalar. A file path or bare name. The directory and the extension are removed before splitting.

fields

Character vector of output column names, in the order the parts appear in the name.

sep

Character scalar. Literal separator between parts. Default "_".

on_fail

What to do when the name does not split into exactly length(fields) non-empty parts: "skip" (default) returns NULL, "error" throws, "na" returns a one-row tibble of NA_character_.

Value

A one-row tibble with one character column per entry of fields, or NULL (see on_fail).

Details

A name matches only when it splits into exactly length(fields) non-empty parts. That strictness is the point: it is what lets a directory read reject stray files (repeat takes such as ID003_K_K_KG60_MH_R01, notes, exports) instead of silently mislabelling them.

See also

Other Pliance ingest functions: pr_read_dir(), pr_read_pliance()

Examples

fields <- c("ID", "Saddle", "Pad", "Weight", "Mode")
pr_meta_from_filename("ID052_K_K_KG00_MS.asc", fields)
#> # A tibble: 1 × 5
#>   ID    Saddle Pad   Weight Mode 
#>   <chr> <chr>  <chr> <chr>  <chr>
#> 1 ID052 K      K     KG00   MS   

# A repeat take carries a sixth part, so it does not match:
pr_meta_from_filename("ID003_K_K_KG60_MH_R01.asc", fields)
#> NULL

pr_meta_from_filename("ID003_K_K_KG60_MH_R01.asc", fields, on_fail = "na")
#> # A tibble: 1 × 5
#>   ID    Saddle Pad   Weight Mode 
#>   <chr> <chr>  <chr> <chr>  <chr>
#> 1 NA    NA     NA    NA     NA