How do I find a common substring between two strings?

Question

y = "dee"
x = "ree"

I want to right a function that accepts 2 parameters like above and identify the same patterns they have in this case its only

ee

Answer 1

Assuming your two input strings be only text, we can try concatenating the strings together with some unique separator, and then use a regex approach:

y = "dee"
x = "ree"
inp = x + '|' + y
output = re.findall(r'^.*?([^|]+).*\|.*?\1.*$', inp)
print(output)  # ['ee']