Thanks for that, yes you're write I was being dumb. Just to give an example of how slooooow, reading a 48mb csv files with a mixture of strings and numbers with DataFrames's readtable, then writing it gives:
*julia> **@time writetable("data.csv", r)* elapsed time: 3.539380236 seconds (77981180 bytes allocated) *julia> **@time serialize(open("data.dat", "w"), r)* elapsed time: 83.743085747 seconds (3439332792 bytes allocated) Lots of time seems to be spent in string.jl >> print_escaped. Surely there is some improvement that can be made to this? If print_escape is the bottle neck couldn't it be rewritten in c?