List the datasets in a file or directory

Inventory the dataset(s) a path contains, one row per dataset, dispatched by extension through the same codec registry as read_dataset(). A SAS XPORT library lists every member; a single-dataset file (.json, .ndjson, .parquet, .rds) reports one row; a directory inventories each dataset file it holds. The format-neutral companion to the xpt-specific xpt_members().

Usage

members(path)

Arguments

path

A dataset file or a directory. <character(1)>: required. A path to a dataset file (.xpt, .json, .ndjson, .parquet, .rds) or to a directory holding such files. A path that does not exist, or a file whose extension no codec claims, aborts.

Value

A <artoo_members> data frame, one row per dataset, with columns file (source basename), member (dataset name), label, records (row count), variables (column count), and format (the codec format). Empty when a directory holds no dataset files. It is an ordinary data frame underneath.

Details

One dataset per file, except XPORT. XPORT is the only multi-dataset container artoo handles, so only an .xpt path can return more than one row. Every other format is one dataset per file.

A directory is inventoried, not descended. Only the files directly in the directory are listed (no recursion); files whose extension no codec claims are skipped, and a directory with no dataset files returns an empty inventory rather than aborting. A dataset file that fails to read aborts with its codec's error, naming the file.

Note: counting records reads the file through its codec (the one lossless reader), so members() is an honest count, not a header guess; for a large directory it reads every dataset.

See also

Members of one XPORT file: xpt_members().

Per-variable attributes: columns() for one dataset's variable pane.

Examples

dm <- apply_spec(cdisc_dm, sdtm_spec, "DM", conformance = "off")
#> 1 variable the spec declares is absent from the data (not added):
#> `BRTHDTC`.

# ---- Example 1: one dataset in a file ----
#
# A single-dataset format reports exactly one member.
p <- tempfile(fileext = ".json")
write_json(dm, p)
members(p)
#> <artoo_members> 1 dataset
#> file                   member  label         records  variables  format
#> file1a7d71b74d22.json  DM      Demographics  60       25         json

# ---- Example 2: every dataset in a directory ----
#
# Point members() at a folder to inventory each dataset file it holds, one
# row per dataset, dispatched by extension.
dir <- tempfile("datasets")
dir.create(dir)
write_json(dm, file.path(dir, "dm.json"))
write_rds(dm, file.path(dir, "dm.rds"))
members(dir)
#> <artoo_members> 2 datasets
#> file     member  label         records  variables  format
#> dm.json  DM      Demographics  60       25         json
#> dm.rds   DM      Demographics  60       25         rds