remove characters from a string

Question

So there's a facebook challenge that asks users to write their name without certain letters. I decided to write this in C# so everyone wouldn't need to manually remove the letters, however, if you type repeated characters it always fails to remove 1.
Use "fffffff" as an example, it'll print "f". Why?
https://code.sololearn.com/ci9VR2h5DqP5/?ref=app

Answer 1

I think this works :D

https://code.sololearn.com/cE13xM3Yl4TV/#cs

Answer 2

-1 would make string with length 1, processed in the for loop.

Answer 3

Daniel Cooper I have another way to achieve character filtering using regex.

https://code.sololearn.com/cVkuXVH1Yemx/?ref=app

Answer 4

Calviղ Oh, I already figured it out, I also found out you can do it inline, check out my code
https://code.sololearn.com/cZVGMlqI1mZ5/?ref=app

Answer 5

What is your expected output?
Can you Add a sample...

Answer 6

Steven M It does but why does -1 work? I'm so confused

Answer 7

Calviղ Can you make that case insensitive? That's why I didn't use regex, I couldn't figure it out, lol

Answer 8

Daniel Cooper for case insensitive, use
string filtered = Regex.Replace(name, rg, "", RegexOptions.IgnoreCase);

Chack out all the regex options here https://docs.microsoft.com/en-us/dotnet/standard/base-types/regular-expression-options

Answer 9

Daniel Cooper Interesting finding 👍