Export an array to a CSV file in Julia

20
votes

Given a (2d) array A how to export it into a CSV file with Julia?

Back in the older versions, I would write 

writecsv( "FileName.csv",  A);

which would dump the array A into the given file. This, however, does not work in version >= 1.0. After some googling, I also tried to use the CSV module doing

f = open("test.csv", "a+");
CSV.write(f, A; delim = ',')

but this throws an error

ERROR: ArgumentError: no default `Tables.rows` implementation for type: Array{Int64,2}

(my array A was of type Int64).

Does anyone have a working solution for this most trivial question?

1
arraysjuliaexport-to-csv

1 Answers

29
votes

You need to load DelimitedFiles module and now only writedlm function is supported.

So in order to write an array as CSV file use:

julia> using DelimitedFiles

julia> writedlm( "FileName.csv",  A, ',')

To get the same result with CSV.jl package use:

julia> using CSV, Tables

julia> CSV.write("FileName.csv",  Tables.table(A), writeheader=false)

as Matrix does not support Tables.jl interface so you need to wrap it with Tables.table.