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m = [] initializes an empty array of dimension 1. I want to initialize an empty array of dimension 2 (to which I'll append values later on. Is this possible?
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To initialize an empty array, it is perfectly valid to use n = 0 in the above expressions. A possible source of errors would be to confuse this array with an empty array of “Any” type, which is initialized as follows: v = [] # Same as Any[], and you can't change this type easily later (gotcha!)
A 1D array can be created by simply writing array elements within square brackets separated by commas(, ) or semicolon(;). A 2D array can be created by writing a set of elements without commas and then separating that set with another set of values by a semicolon.
Using Designated Initializers Its usage is demonstrated below, where the code explicitly initializes the first element of the array, and the remaining elements are automatically initialized with 0. That's all about initializing a 2D array with zeroes in C.
Julia provides a very simple notation to create matrices. A matrix can be created using the following notation: A = [1 2 3; 4 5 6]. Spaces separate entries in a row and semicolons separate rows. We can also get the size of a matrix using size(A).
As of Julia 1.0 you can use:
m = Array{Float64}(undef, 0, 0) for an (0,0)-size 2-D Matrix storing Float64 values and more in general:
m = Array{T}(undef, a, b, ...,z) for an (a,b,...,z)-size multidimensional Matrix (whose content is garbage of type T).
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Try:
m = reshape([],0,2) or,
m = Array{Float64}(undef, 0, 2) The second option which explicitly defines type should generate faster code.
A commenter ephemerally suggested using Matrix() for a 0x0 matrix and Matrix(0,2) for a 0x2 matrix.
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