Export data with the number form but is not same as shown in notebook

Question

I want to export data nicely with NumberForm, However it displays Ok in the note book, but not the exported file.

Here is the code:

lst = {{1/10, 1/3}, {1/3, Pi}};
lst = N[lst, 10]
SetDirectory[NotebookDirectory[]];
Export["testlst.txt", lst, "Table"];

The output in the notebook is:

{{0.1000000000, 0.3333333333}, {0.3333333333, 3.141592654}}

However in the txt file it looks like(ugly, not easy to read):

0.1 0.3333333333
0.3333333333    3.141592654

How to fix this? or How to achieve the format specification such as %15.4lf like in c?

Answer 1

I mapped NumberForm, padding to the left with spaces and to the right with zeroes, at the lowest level of your table

numbers = 
  Map[
    NumberForm[#, {11, 10}, NumberPadding -> {" ", "0"}] &, 
    N[{{1/10, 1/3}, {1/3, Pi}}, 10], 
    {-1}]

and then exported it to my desktop

Export[FileNameJoin[{$HomeDirectory, "Desktop", "test.txt"}], numbers, "Table"]

The output file looked like this:

which I think is pretty much what you want.