I don't see any code here.

However, if your vector of wavelengths is wl=fltarr(N), where N is number of wavelengths, and spectrum=fltarr(N), so both have the same dimensions, In that case, you can print to the screen like:
for i=0,n-1 do print,wl,spec
which will print in two columns, separated by white space.

I that the easiest way to do this is to use PRINTF using C formatting to put the output into columns. An example is shown below:

pro dj_forum_20102017
compile_opt idl2

a = findgen(10)
b = findgen(10)

a = transpose(a)
b = transpose(b)

;print output to console
print,a,b,FORMAT="%f %f"

;print output to file
openw,lun, "output.txt", /GET_LUN
printf, lun, a,b,FORMAT="%f %f"
FREE_LUN, lun

end


David Starbuck
-Harris