This is part of the read syntax:
julia> 10_000_000
10000000
but how can I print numbers in this format? Just want integers.
PS.: I can work around this with
julia> using Formatting
julia> replace(format(10^7, commas = true), ",", "_")
"10_000_000"
or similar hacks.
You can try something like:
julia> @eval Base begin
using Formatting
show(io::IO, i::Signed) = show(io, replace(format(i, commas=true), ",", "_"))
end;
WARNING: Method definition show(IO, Signed) in module Base at show.jl:259 overwritten at REPL[1]:3.
rand(1:10000, 5, 5)
5×5 Array{Int64,"2"}:
"6_475" "7_306" "1_793" "2_164" "2_441"
"7_282" "9_051" "2_813" "5_542" "3_969"
"6_739" "5_924" "4_357" "1_587" "288"
"487" "8_289" "9_454" "8_507" "305"
"4_025" "5_789" "1_285" "1_833" "9_989"
It will probably break many things though (including the REPL) 
Perhaps I was not clear (sorry): I am not looking for a solution to change this everywhere, just to print a specific number. I was just surprised that I could not find anything in Base that would support printing in a syntax it reads.
In that case, I think something like Formatting is the correct tool.