Regular expression for changing spaces to tabs in Notepad++

Question

I'm trying to use regular expression in Notepad++ to change spaces to tabs in something like this

01 fsdfsd

01 01 fsdfsd

01 01* fsdfsd

01 01 01 fsdfsd

01 01 01* fsdfsd

How can I keep spaces between numbers and change only the last space?

Thanks.

Answer 1

Search for:

[ ]([a-zA-Z])

(Note that there is a space in front of the character class.) And replace with:

\t$1

An alternative that might be better suited if you also have lines that are of a different format, or if fsdfsd may contain spaces, is this:

^((?:\d+\*?)(?:[ ]\d+\*?)*)[ ]

Now replace with

$1\t

This matches any space after the longest possible string of digits with optional asterisks separated by spaces.