Regular expression to combine numbers

Question

I have a sequence of numbers as shown below. I want to combine the numbers into a group of 4. Can someone give a vim regex for this?

Entrance: 1234 56 7890 1234

The output should be: 1234 5678 9012 34

Answer 1

Two passes:

s/ //g
s/\(.\{4\}\)/\1 /g

Answer 2

I would do this in two steps: (1) remove spaces to the right of groups of numbers

:s/\(\d\+\) /\1/g

(2) grouping:

:s/\(\d\{4}\)/\1 /g

In the case where many lines record a macro or follow these steps for the marked area.

Answer 3

, :

:s/\(\d\) *\(\d\) *\(\d\) *\(\d\) */\1\2\3\4 /g

, asinine. , 2 Monsteregex ™, . , .

Answer 4

:s/\(\d\)\s*\(\d\)\s*\(\d\)\s*\(\d\)\s*/\1\2\3\4 /g

, .