Add nrow and ncol

Project.toml

@@ -1,7 +1,7 @@
 name = "Tables"
 uuid = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 authors = ["quinnj <[email protected]>"]
-version = "1.7.0"
+version = "1.8.0"
 
 [deps]
 DataAPI = "9a962f9c-6df0-11e9-0e5d-c546b8b5ee8a"

docs/src/index.md

@@ -277,6 +277,8 @@ matrix(m::MatrixTable) = getfield(m, :matrix)
 lookup(m::MatrixTable) = getfield(m, :lookup)
 # schema is column names and types
 Tables.schema(m::MatrixTable{T}) where {T} = Tables.Schema(names(m), fill(eltype(T), size(mat(m), 2)))
+Tables.ncol(m::MatrixTable) = size(m.matrix, 2)
+Tables.nrow(m::MatrixTable) = size(m.matrix, 1)
 ```
 
 Here we defined `Tables.istable` for all `MatrixTable` types, signaling that they implement the Tables.jl interfaces.

src/Tables.jl

@@ -32,6 +32,7 @@ Interface definition:
 | `Tables.columnnames(table)`                              | propertynames(table)        | Return column names for a table as an indexable collection                                                                                                   |
 | **Optional methods**                                     |                             |                                                                                                                                                              |
 | `Tables.getcolumn(table, ::Type{T}, i::Int, nm::Symbol)` | Tables.getcolumn(table, nm) | Given a column eltype `T`, index `i`, and column name `nm`, retrieve the column. Provides a type-stable or even constant-prop-able mechanism for efficiency. |
+| `Tables.ncol(table)`                                     | Tables.ncol(table)          | Return the number of columns                                                                                                                                 |
 
 Note that subtypes of `Tables.AbstractColumns` **must** overload all required methods listed
 above instead of relying on these methods' default definitions.
@@ -65,6 +66,7 @@ Interface definition:
 | `Tables.columnnames(row)`                              | propertynames(row)        | Return column names for a row as an indexable collection                                                                                                         |
 | **Optional methods**                                   |                           |                                                                                                                                                                  |
 | `Tables.getcolumn(row, ::Type{T}, i::Int, nm::Symbol)` | Tables.getcolumn(row, nm) | Given a column element type `T`, index `i`, and column name `nm`, retrieve the column value. Provides a type-stable or even constant-prop-able mechanism for efficiency. |
+| `Tables.ncol(row)`                                     | length(propertynames(row) | Return number of columns                                                                                                                                         |
 
 Note that subtypes of `Tables.AbstractRow` **must** overload all required methods listed above
 instead of relying on these methods' default definitions.
@@ -413,6 +415,23 @@ See also [`rowtable`](@ref) and [`namedtupleiterator`](@ref).
 """
 function rows end
 
+"""
+    nrow(cols::AbstractColumns)
+
+Returns the number of rows in an object that satisfies the `AbstractColumns` interface
+as returned from `Tables.columns(tbl)`. Note that this isn't valid to call on _any_ valid
+Tables.jl source as row-oriented tables may not have a defined length.
+"""
+function nrow end
+
+"""
+    ncol(rows::AbstractRows)
+
+Returns the number of columns in an object that satisfies the `AbstractRows` interface
+as returned from `Tables.rows(tbl)`.
+"""
+function ncol end
+
 # Schema implementation
 """
     Tables.Schema(names, types)

src/dicts.jl

@@ -93,6 +93,7 @@ schema(x::DictColumnTable) = getfield(x, :schema)
 columnnames(x::DictColumnTable) = getfield(x, :schema).names
 getcolumn(x::DictColumnTable, i::Int) = getfield(x, :values)[columnnames(x)[i]]
 getcolumn(x::DictColumnTable, nm::Symbol) = getfield(x, :values)[nm]
+ncol(x::DictColumnTable) = length(columnnames(x))
 
 struct DictRowTable
     names::Vector{Symbol}
@@ -111,6 +112,7 @@ end
 columnnames(x::DictRow) = getfield(x, :names)
 getcolumn(x::DictRow, i::Int) = get(getfield(x, :row), columnnames(x)[i], missing)
 getcolumn(x::DictRow, nm::Symbol) = get(getfield(x, :row), nm, missing)
+ncol(x::DictRow) = length(columnnames(x))
 
 Base.IteratorSize(::Type{DictRowTable}) = Base.HasLength()
 Base.length(x::DictRowTable) = length(getfield(x, :values))

src/fallbacks.jl

@@ -5,6 +5,7 @@
 # Turn any AbstractColumns into an AbstractRow iterator
 
 # get the number of rows in the incoming table
+# this function is internal
 function rowcount(cols)
     names = columnnames(cols)
     isempty(names) && return 0
@@ -241,6 +242,7 @@ getcolumn(x::CopiedColumns, ::Type{T}, col::Int, nm::Symbol) where {T} = getcolu
 getcolumn(x::CopiedColumns, i::Int) = getcolumn(source(x), i)
 getcolumn(x::CopiedColumns, nm::Symbol) = getcolumn(source(x), nm)
 columnnames(x::CopiedColumns) = columnnames(source(x))
+ncol(x::CopiedColumns) = length(columnnames(x))
 
 # here's our generic fallback Tables.columns definition
 @inline function columns(x::T) where {T}

src/matrix.jl

@@ -41,6 +41,8 @@ columnnames(m::MatrixRow) = names(getfield(m, :source))
 schema(m::MatrixTables{T}) where {T} = Schema(Tuple(names(m)), NTuple{size(getfield(m, :matrix), 2), eltype(T)})
 Base.eltype(m::MatrixRowTable{T}) where {T} = MatrixRow{T}
 Base.length(m::MatrixRowTable) = size(getfield(m, :matrix), 1)
+ncol(m::MatrixTable) = size(getfield(m, :matrix), 2)
+nrow(m::MatrixTable) = size(getfield(m, :matrix), 1)
 
 Base.iterate(m::MatrixRowTable, st=1) = st > length(m) ? nothing : (MatrixRow(st, m), st + 1)
 

src/namedtuples.jl

@@ -108,7 +108,7 @@ end
 
 # NamedTuple of arrays of matching dimensionality
 const ColumnTable = NamedTuple{names, T} where {names, T <: NTuple{N, AbstractArray{S, D} where S}} where {N, D}
-rowcount(c::ColumnTable) = length(c) == 0 ? 0 : length(c[1])
+nrow(c::ColumnTable) = length(c) == 0 ? 0 : length(c[1])
 
 # interface implementation
 istable(::Type{<:ColumnTable}) = true

test/runtests.jl

@@ -261,6 +261,8 @@ Tables.schema(x::MockTable) = Tables.Schema((:a, :b, :c), NTuple{3, Int})
     @test Tables.getcolumn(matrow, :Column1) == 1
     @test Tables.getcolumn(matrow, 1) == 1
     @test propertynames(mattbl) == propertynames(matrow) == [:Column1, :Column2, :Column3]
+    @test Tables.nrow(mattbl) == 3
+    @test Tables.ncol(mattbl) == 3
 
     mattbl = Tables.table(mat, header=[:A, :B, :C])
     @test Tables.columnnames(mattbl) == [:A, :B, :C]