DefaultArray(default, size...)

Create a DefaultArray

Example 1:

julia> DefaultArray("X",3,3)
3×3 DefaultArray{String,2}:
 "X"  "X"  "X"
 "X"  "X"  "X"
 "X"  "X"  "X"

Example 2:

julia> DefaultArray(false,3,4)
3×4 DefaultArray{Bool,2}:
 0  0  0  0
 0  0  0  0
 0  0  0  0

DefaultArray(default, A::AbstractArray)

Example 3:

DefaultArray(false,rand(Bool,5,5))
5×5 DefaultArray{Bool,2}:
1  0  0  1  0
1  1  1  1  1
1  1  1  0  0
0  1  0  0  1
0  0  1  1  0

eachnondefault(A::DefaultArray, indexstyle = IndexLinear())

Create an generator object for visiting each index of a DefaultArray A containing a non-default value, in an efficient manner.

Example:

julia> A = DefaultArray(1,[1 2; 3 4]);

julia> for i in eachnondefault(A) # linear indexing
           println(i, " ", A[i])
       end
4 4
2 3
3 2

notice how the value "1" has been skipped, since we set 1 as the default value.

julia> A = DefaultArray(1,[1 2; 3 4]);

julia> for i in eachnondefault(A,IndexCartesian()) # cartesian indexing
           println(i, " ", A[i])
       end
CartesianIndex(2, 2) 4
CartesianIndex(2, 1) 3
CartesianIndex(1, 2) 2