Why does not this code work when I delete "r" in line 3?

Question

https://code.sololearn.com/cd7odtnF0nJG/?ref=app

Answer 1

the r stands for Regular Expression. Once you remove it you are looking for a substring 'g.y' which is not found in your cases. With the r you are matching a regex that searches for a substring that matches the pattern letter 'g' followed by any character, followed by the letter 'y'.

Answer 2

@Kuba - now when I think about it it makes perfect sense 🤗 wonder where I got that from. Of course that makes my previous post a complete rubbish 😃

Answer 3

Nikolay Actually, r stands for "raw string literal", that is, the exact form of the string is represented by it - no escape characters, no special characters, just raw, exact (byte) representation.
The 're' module uses rawstrings for patterns as they are the safest way to go - regex have to take string literals and not to worry about what the \n means ;)

Answer 4

example,please.
r"g.y" and "g.y" matches "gXy" and "g.y", but not "gX/ny" or "g./ny"