Pasting "rectangles" of text side-by-side

Question

In Emacs/Xemacs, there is a rectangle feature, such that you can delete, copy, etc., "rectangles" of text.

Now suppose I have two text files, each containing one column of numbers. Is it possible to use Mathematica to "paste" the columns of text, side by side (perhaps separated by at least one space)?

For example, suppose I have two text files:

(* file 1 *)
1
20
300

(* file 2 *)
4
50
600

I would like to be able to obtain a single text file like this:

(* file 3 *)
1   4
20  50
300 600

Do you have any ideas of how I can do this efficiently? The ideas I have (like stripping and joining row-by-row, and adding the appropriate number of spaces) are really complicated, and I feel like there must be an easier way. Thanks!

Answer 1

I think you can just do this:

file1dat = Import["file1.txt", "Table"];
file2dat = Import["file2.txt", "Table"];
file3dat = Import["file3.txt", "Table"];
Export["output.txt", Join[file1dat, file2dat, file3dat, 2]];

Edit: Here's a better solution, which will place the entire lines of text (regardless of whether there is whitespace within a line) next to each other, separated by one space. You can change the Riffle call to put whatever character you like between the strings:

files = {"file1.txt", "file2.txt", "file3.txt"};
Export["output.txt", Transpose@{StringJoin@Riffle[#, " "] & /@
    Transpose[StringSplit[Import[#, "Text"], "\n"] & /@ files]}, "Table"]

Answer 2

If you are on Linux then this is an option:

$paste file?.txt > output.txt

Just use paste to join the files together.

Which in Mathematica speak is:

Run["paste file?.txt > output.txt"]