How to find overlapping patterns in a regex?

Question

Suppose I have a string like this 123456789. Is there any way to find the every possible existing pattern from the given string like this

1234, 2345, 3456,4567, 5678, 6789 using regex

I did this but couldn't figure out the solution:

import re
regex = r"[1-9]{4}"
test_string = "123456789"
print(re.findall(regex, test_str))

this outputs:

['1234', '5678']

Any help will mean a lot to me, Thanks

Answer 1

You can try this regex:

\d(?=(\d{3}))

Regex Demo

Sample Source (Run here )

import re
regex = r"\d(?=(\d{3}))"
test_str = "123456789"
matches = re.finditer(regex, test_str)

for match in matches:
 print(match.group()+match.group(1));