fst Format

Read R fst columnar on-disk data frames as flat row dictionaries.

Overview

Property	Value
Format id	fst
Class	FSTIterable
Extensions	.fst
Read	Yes
Write	No
Extra	fst (fst or rfst binding)
Maturity	experimental

Parameters

Parameter	Description
columns	Optional column subset passed to the fst reader when supported

The entire frame is loaded into memory (not streaming). Requires a filename path.

Usage

from iterable import open_iterable

with open_iterable("frame.fst", format="fst") as source:
    for row in source:
        print(row)

with open_iterable(
    "frame.fst",
    format="fst",
    iterableargs={"columns": ["id", "value"]},
) as source:
    for row in source:
        print(row)

Install with pip install iterabledata[fst] (or install a compatible fst / rfst binding).

Error Handling

• Missing dependency: optional libraries raise ImportError with an install hint (pip install 'iterabledata[<extra>]' when an extra exists).
• Read-only: opening with mode="w" raises WriteNotSupportedError or ValueError.
• Bad or unsupported input: may raise ValueError, OSError, or library-specific errors.
• See Troubleshooting for decoding, detection, and engine issues.

See also

• RDS / RData — R serialized objects
• Parquet — columnar storage
• Supported formats