Contents

0.1 Zarr version

Support for Zarr version 3 is actively being worked on, and some features are likely to be missing.

It is known that the sharding codec is not yet implemented.

0.2 Reading and Writing

Reading Zarr arrays is reasonably well supported. Writing is available, but is more limited. Both aspects are under active development.

0.2.1 Stores

Store Type Status
(reading / writing)		 Notes
FilesystemStore ✔ / ✔
S3Store ✔ / ❌

0.2.2 Data Types

Currently there is only support for reading and writing a subset of the possible datatypes that can be found in a Zarr array. In some instances there are also limitations on the datatypes natively supported by R, requiring conversion from the Zarr datatype. The table below summarises the current status of datatype support. It will be updated as progress is made.

Zarr Data Type Status
(reading / writing)		 Notes
boolean ✔ / ✔ (via {grumpy})
int8 ✔ / ✔ (via {grumpy})
uint8 ✔ / ✔ (via {grumpy})
int16 ✔ / ✔ (via {grumpy})
uint16 ✔ / ✔ (via {grumpy})
int32 ✔ / ✔ (via {grumpy})
uint32 ✔ / ✔ (via {grumpy})
int64 ✔ / ✔ (via {grumpy})
uint64 ✔ / ✔ (via {grumpy})
half / float16 ✔ / ❌ (via {grumpy})
single / float32 ✔ / ✔ (via {grumpy})
double / float64 ✔ / ✔ (via {grumpy})
complex ❌ / ❌
timedelta ❌ / ❌
datetime ❌ / ❌
V2 string ✔ / ✔ (via {grumpy})
V3 null_terminated_bytes ✔ / ✔ (via {grumpy})
V2 Unicode ✔ / ✔ (via {grumpy})
V3 fixed_length_utf32 ✔ / ✔ (via {grumpy})
void * ❌ / ❌
V2 structured data types ✔ / ❌ (via {grumpy})
V3 structured data types ✔ / ❌ This type is superseded by V3 struct data types.and the specification says implementation MUST NOT implement writing. (via {grumpy})
V3 struct data types ✔ / ❌ (via {grumpy})

0.2.3 Codecs

0.2.3.1 Compression codecs

Library Status
(reading / writing)		 Notes
zlib / gzip ✔ / ✔
bzip2 ✔ / ✔
blosc ✔ / ✔
LZMA ✔ / ✔
LZ4 ✔ / ✔
Zstd ✔ / ✔

Please open an issue if support for a required compression codec is missing.

0.2.3.2 Other codecs

Codec Status
(reading / writing)		 Notes
endian ✔ / ❌ (via {grumpy})
transpose ✔ / ✔
VLen-UTF8 ✔ / ✔ * Writing supported only via update_zarr_array()

0.2.4 Optional fields or features

Feature Status
(reading / writing)		 Notes
dimension_names ✔ / ✔ Corresponds to names(dimnames(x)) in R