Write YAXArrays and Datasets

Create an example Dataset:

using YAXArrays
using NetCDF
using Downloads: download

path = download("https://www.unidata.ucar.edu/software/netcdf/examples/tos_O1_2001-2002.nc", "example.nc")
ds = open_dataset(path)
YAXArray Dataset
Shared Axes: 
↓ lon Sampled{Float64} 1.0:2.0:359.0 ForwardOrdered Regular Points,
→ lat Sampled{Float64} -79.5:1.0:89.5 ForwardOrdered Regular Points,
↗ Ti  Sampled{CFTime.DateTime360Day} [CFTime.DateTime360Day(2001-01-16T00:00:00), …, CFTime.DateTime360Day(2002-12-16T00:00:00)] ForwardOrdered Irregular Points
Variables: 
tos

Properties: Dict{String, Any}("cmor_version" => 0.96f0, "references" => "Dufresne et al, Journal of Climate, 2015, vol XX, p 136", "realization" => 1, "Conventions" => "CF-1.0", "contact" => "Sebastien Denvil, sebastien.denvil@ipsl.jussieu.fr", "history" => "YYYY/MM/JJ: data generated; YYYY/MM/JJ+1 data transformed  At 16:37:23 on 01/11/2005, CMOR rewrote data to comply with CF standards and IPCC Fourth Assessment requirements", "table_id" => "Table O1 (13 November 2004)", "source" => "IPSL-CM4_v1 (2003) : atmosphere : LMDZ (IPSL-CM4_IPCC, 96x71x19) ; ocean ORCA2 (ipsl_cm4_v1_8, 2x2L31); sea ice LIM (ipsl_cm4_v", "title" => "IPSL  model output prepared for IPCC Fourth Assessment SRES A2 experiment", "experiment_id" => "SRES A2 experiment"…)

Write Zarr

Save a single YAXArray to a directory:

using Zarr
savecube(ds.tos, "tos.zarr", driver=:zarr)

Save an entire Dataset to a directory:

savedataset(ds, path="ds.zarr", driver=:zarr)

Write NetCDF

Save a single YAXArray to a directory:

using NetCDF
savecube(ds.tos, "tos.nc", driver=:netcdf)

Save an entire Dataset to a directory:

savedataset(ds, path="ds.nc", driver=:netcdf)

Overwrite a Dataset

If a path already exists, an error will be thrown. Set overwrite=true to delete the existing dataset

savedataset(ds, path="ds.zarr", driver=:zarr, overwrite=true)

::: danger

Again, setting overwrite will delete all your previous saved data.

:::

Look at the doc string for more information

YAXArrays.Datasets.savedataset — Function

savedataset(ds::Dataset; path = "", persist = nothing, overwrite = false, append = false, skeleton=false, backend = :all, driver = backend, max_cache = 5e8, writefac=4.0)

Saves a Dataset into a file at path with the format given by driver, i.e., driver=:netcdf or driver=:zarr.

Warning

overwrite = true, deletes ALL your data and it will create a new file.

Append to a Dataset

New variables can be added to an existing dataset using the append=true keyword. 

ds2 = Dataset(z = YAXArray(rand(10,20,5)))
savedataset(ds2, path="ds.zarr", backend=:zarr, append=true)
Save Skeleton
Sometimes one merely wants to create a datacube  "Skeleton" on disk and gradually fill it with data. Here we make use of FillArrays to create a YAXArray and write only the axis data and array metadata to disk, while no actual array data is copied:
using YAXArrays, Zarr, FillArrays
create the Zeros array
and save them as
r = savecube(a, "skeleton.zarr", driver=:zarr, skeleton=true)
and check that all the values are missing
all(ismissing,r[:,:])
true
If using FillArrays is not possible, using the zeros function works as well, though it does allocate the array in memory.
::: info
The skeleton argument is also available for savedataset. 
:::