How to remove everything but letters?

Question

Regular Expressions

Let's say we have a string: "ПРИВЕТ!!!2222312HELLO MY NAME IS habr!!".
How to get from such a string "ПРИВЕТHELLOMYNAMEIShabr"using a regular expression?

Answer 1

Regex.Replace(str, "(?i)[^А-ЯЁA-Z]", "")

Answer 2

It is worth looking here to fix it:
https://docs.microsoft.com/ru-ru/dotnet/standard/b...
https://habr.com/ru/company/otus/blog/469989/
https:// metanit.com/sharp/tutorial/7.4.php

Answer 3

for a change https://ideone.com/h7RtVy

Answer 4

Why not immediately use complex neural networks?
Why is Replace objectionable?