import re
regex = r"(?<=\b)\d+(?=[\s.,])"
test_str = "Hi I am sony. My age 23. This is my email id sony.1510@gmail.com . Hi I am Jessey. My age 20. This is my email id jessey.1996@gmail.com . Hi I am ronald.My age 17 My mail id is ronald.1999@gmail.com"

matches = re.finditer(regex, test_str, re.MULTILINE)

for match in matches:
	print(match.group(0))