Why regex does not return overlapped matches

Question

I have the following regex expression:

[0-7]{2}

For the following string 234212, I get three matches:

23   
42
12

I don't understand why I don't get also 34, 12?

Answer 1

You can try this:

(?=([0-7]{2}))

The above regex captures every valid pair in group 1 , I have used the positive look-ahead to achieve this as this helps to match without moving the cursor forward.

Demo