I have a little program that correctly produces a sparse matrix from data. When I call the result: display(dataOut) I get the expected: 3×3 SparseMatrixCSC{Float64, Int64} with 3 stored entries: -1.0 -1.0 ⋅ -1.23 ⋅ ⋅ ⋅ ⋅ ⋅ Now I want to export that to a .csv file using wr…

Ok, could you try this: using SparseArrays, DelimitedFiles M = sprand(5, 5, 0.5) Md = Matrix(M) # creates dense Matrix{Float64} Mb = similar(Md,Any) # similar Matrix{Any}, type Any allows mixing floats with strings Mb .= Md # assigns content of Md to Mb Mb[Md .== 0] .= ""…

Thanks for the suggestion. Using dataframes like this doesn’t produce the correct behavior I’m afraid: df = DataFrame([dataOut]) CSV.write("Output.csv", df) I’m not sure if I am doing something wrong here, but I specifically want the data to be “clean”, as it were. So I don’t want a dataframe wi…

Still doing it, I’m afraid. I tried a couple of variations. When I try your code directly it throws the following: ERROR: LoadError: ArgumentError: column name :V not found in the data frame; existing most similar names are: :m and :n

Ah, that runs now, not sure what I did wrong. However, now it is not observing the rows and columns, just outputting everything in one row in the .csv [Will edit previous posts for formatting, thanks for the heads up]

Perfect. Thanks! Now I’m going to have to spend the rest of the day trying to figure out why that works :grinning:

Added some comments to the code, in case it helps.

Thanks! So basically, it’s a dense matrix with blanks instead of zeros? If so, that might actually be more useful to me in the long run.

Yes, it is a weird dense matrix of Any which was made up just to satisfy your CSV output request. Cannot see any other use for it, honestly speaking.

At the moment I’m just using Excel’s conditional formatting on it, otherwise I have to run a macro to get rid of the zeros on the other end. Eventually this step will probably be redundant if I can get the whole thing to run in its own app, but for now this is great. Thanks again!

Tables.table(mat) will wrap a matrix in a tables-compatible object for use with CSV.write. As for zeros versus missing for the sparse entries, I think there is a package for that, but googling hasn’t gotten me there. But if you can make a sparse matrix where the zero-values are missing, you can pas…

Output sparse matrix to csv

General Usage

rafael.guerra September 1, 2021, 5:06pm 2

See solution in this post.

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Output sparse matrix to csv

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