Indexing, subsetting and selectors

All these operations are done via DimensionalData.jl.

using YAXArrays, Dates

Define a toy cube

julia> t = Date("2020-01-01"):Month(1):Date("2022-12-31")

Date("2020-01-01"):Dates.Month(1):Date("2022-12-01")

julia> axes = (Dim{:lon}(-9:10), Dim{:lat}(-5:15), Dim{:time}(t))

↓ lon  -9:10,
→ lat  -5:15,
↗ time Date("2020-01-01"):Dates.Month(1):Date("2022-12-01")

julia> c = YAXArray(axes, reshape(1:20*21*36, (20, 21, 36)))

╭────────────────────────────╮
│ 20×21×36 YAXArray{Int64,3} │
├────────────────────────────┴─────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} -9:10 ForwardOrdered Regular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} Date("2020-01-01"):Dates.Month(1):Date("2022-12-01") ForwardOrdered Regular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 118.12 KB
└──────────────────────────────────────────────────────────────────────────────┘

A very convinient selector is lookup, getting for example the values for lon and time.

lookup

lon = lookup(c, :lon)

Sampled{Int64} ForwardOrdered Regular DimensionalData.Dimensions.Lookups.Points
wrapping: -9:10

tempo = lookup(c, :time)

Sampled{Date} ForwardOrdered Regular DimensionalData.Dimensions.Lookups.Points
wrapping: Date("2020-01-01"):Dates.Month(1):Date("2022-12-01")

Selectors

At value

julia> c[time = At(DateTime("2021-05-01"))]

╭─────────────────────────╮
│ 20×21 YAXArray{Int64,2} │
├─────────────────────────┴─────────────────────────── dims ┐
  ↓ lon Sampled{Int64} -9:10 ForwardOrdered Regular Points,
  → lat Sampled{Int64} -5:15 ForwardOrdered Regular Points
├───────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├──────────────────────────────────────────────── file size ┤
  file size: 3.28 KB
└───────────────────────────────────────────────────────────┘

At vector of values

julia> c[time = At([DateTime("2021-05-01"), DateTime("2021-06-01")])]

╭───────────────────────────╮
│ 20×21×2 YAXArray{Int64,3} │
├───────────────────────────┴──────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} -9:10 ForwardOrdered Regular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} [Date("2021-05-01"), Date("2021-06-01")] ForwardOrdered Irregular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 6.56 KB
└──────────────────────────────────────────────────────────────────────────────┘

similarly for any of the spatial dimensions:

julia> c[lon = At([-9,-5])]

╭───────────────────────────╮
│ 2×21×36 YAXArray{Int64,3} │
├───────────────────────────┴──────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} [-9, -5] ForwardOrdered Irregular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} Date("2020-01-01"):Dates.Month(1):Date("2022-12-01") ForwardOrdered Regular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 11.81 KB
└──────────────────────────────────────────────────────────────────────────────┘

At values with tolerance (atol, rtol)

julia> c[lon = At([-10, 11]; atol = 1)]

╭───────────────────────────╮
│ 2×21×36 YAXArray{Int64,3} │
├───────────────────────────┴──────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} [-9, 10] ForwardOrdered Irregular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} Date("2020-01-01"):Dates.Month(1):Date("2022-12-01") ForwardOrdered Regular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 11.81 KB
└──────────────────────────────────────────────────────────────────────────────┘

Subsetting

This is also done with selectors, see the following examples

Between

Altought a Between(a,b) function is available in DimensionalData, is recommended to use instead the a .. b notation:

julia> c[lon = -9 .. -7] # close interval, all points included.

╭───────────────────────────╮
│ 3×21×36 YAXArray{Int64,3} │
├───────────────────────────┴──────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} -9:-7 ForwardOrdered Regular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} Date("2020-01-01"):Dates.Month(1):Date("2022-12-01") ForwardOrdered Regular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 17.72 KB
└──────────────────────────────────────────────────────────────────────────────┘

More selectors from DimensionalData are available, such as Touches, Near, Where and Contains.

Open/Close Intervals

using IntervalSets

julia> c[lon = OpenInterval(-9, -7)]

╭───────────────────────────╮
│ 1×21×36 YAXArray{Int64,3} │
├───────────────────────────┴──────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} -8:-8 ForwardOrdered Regular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} Date("2020-01-01"):Dates.Month(1):Date("2022-12-01") ForwardOrdered Regular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 5.91 KB
└──────────────────────────────────────────────────────────────────────────────┘

julia> c[lon = ClosedInterval(-9, -7)]

╭───────────────────────────╮
│ 3×21×36 YAXArray{Int64,3} │
├───────────────────────────┴──────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} -9:-7 ForwardOrdered Regular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} Date("2020-01-01"):Dates.Month(1):Date("2022-12-01") ForwardOrdered Regular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 17.72 KB
└──────────────────────────────────────────────────────────────────────────────┘

julia> c[lon =Interval{:open,:closed}(-9,-7)]

╭───────────────────────────╮
│ 2×21×36 YAXArray{Int64,3} │
├───────────────────────────┴──────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} -8:-7 ForwardOrdered Regular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} Date("2020-01-01"):Dates.Month(1):Date("2022-12-01") ForwardOrdered Regular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 11.81 KB
└──────────────────────────────────────────────────────────────────────────────┘

julia> c[lon =Interval{:closed,:open}(-9,-7)]

╭───────────────────────────╮
│ 2×21×36 YAXArray{Int64,3} │
├───────────────────────────┴──────────────────────────────────────────── dims ┐
  ↓ lon  Sampled{Int64} -9:-8 ForwardOrdered Regular Points,
  → lat  Sampled{Int64} -5:15 ForwardOrdered Regular Points,
  ↗ time Sampled{Date} Date("2020-01-01"):Dates.Month(1):Date("2022-12-01") ForwardOrdered Regular Points
├──────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any}()
├─────────────────────────────────────────────────────────────────── file size ┤
  file size: 11.81 KB
└──────────────────────────────────────────────────────────────────────────────┘

See tutorials for use cases.