Changelog • zarr

zarr (development version)

zarr_node::post_open() method allows for processing that requires the Zarr hierarchy to be in place.
Dynamically set a node in a Zarr hierarchy.
Set metadata on a node in a memory store.
Convention classes are now coded as attribute factories.
Fix key listing in memory stores.

CRAN release: 2026-06-14

Hierarchy can now also be printed from any group. Zarr arrays from domain packages may use alternative glyphs.
New attribute() method for zarr_group and zarr_array instances.
Attributes can be nested by specifying a compound path when adding. JSON array attributes can be appended. JSON arrays can be deleted over compound paths, including JSON arrays.
Attributes article updated.

CRAN release: 2026-05-28

Reading of sharded Zarr stores is now supported.
The Zarr-registered “string” data type, an extension to the core specification, is now supported. This uses the “vlen-utf8” codec, also a registered extension to the core specification. For Zarr v.2 stores, this corresponds to the “|O” data type; the “<U*” data type is also supported, using a mocked-up “ucs-4” codec (it is not a true codec or Zarr v.2 filter) to provide the mandatory “array -> bytes” codec. This means that you can now read Zarr arrays that have character data. You can also create new Zarr arrays with character data.
Nested attributes print better to the console.
zarr_conventions() function returns data.frame of supported conventions.
Ref convention code updated.
Malformed “NaN”, “Infinity” and “-Infinity” in metadata solved.
Better testing of fill values.
Fixed deeply nested consolidated metadata.
Fixed handling of scalar arrays.
R dependency bumped to 4.2
Using Rcpp for performance bottlenecks, using future for optional parallel processing of chunks and shards.

CRAN release: 2026-04-18

Extensible domain and convention mechanisms added, following ZEP0004. This enables developers to extend this Zarr implementation with domain-specific interfaces.
Metadata is now writable as a complete object - expert use only.
Fixed listing of keys in memory stores.
Expanded documentation.

CRAN release: 2026-02-11

Zarr version 2 stores can be read. Data types supported are those also included in the v.3 core specification. The compression codec has to be one of those supported by the v.3 core specification or zstd. Filters are not yet supported.
HTTP stores can be read but only for Zarr v.3 and v.2 single-array stores and Zarr v.2 stores with consolidated metadata present in the root group of the Zarr store.
Chunk key encoding from v.2 and “default” and “v2” from v.3 supported.
The blosc package is now imported as it is the default compression codec.
zstd compression codec added.
Fixed reading integer64 data.

CRAN release: 2025-12-06

Initial code base. This release contains a fairly complete implementation of the Zarr core v.3 specification. As such, it will not be able to access Zarr v.2 stores.
Support for adding and deleting attributes to groups and arrays.