Unexpected behavior of the match method with position about crystal HOT 7 CLOSED

Why would you expect this to return nil? bc is valid based on the regex of [a-zA-Z_]+, and is matched because question_mark_position is making it skip the first character, which otherwise would have matched.

So to me it seems this is working as designed.

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@ksg97031 It's unclear to me what you're wanting to do exactly, but maybe https://crystal-lang.org/api/String.html#match_full%28regex%3ARegex%29%3ARegex%3A%3AMatchData%7CNil-instance-method ?

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@Blacksmoke16 @ysbaddaden
Thank you for the answer.

I was confused because I didn't realize that the keyword 'match' can also refer to a specific part or element that corresponds with another.
So, I substituted the code below to achieve what I wanted using a substring without specifying the position:

input = "a?bc"
match = input[position..].match(/^[a-zA-Z_]+/)
if match
  print(match[0])
end

Could you let me know if there is a way to perform a starts_with operation at a specific position that also returns MatchData?

Thank you!

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String#match with a position argument starts searching for a match from that position. But not limited to that position.
If you want the regex match to be anchored, please use the appropriate option: "a????bc".match(/[a-z]+/, 1, options: :anchored) # => nil

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@ksg97031 You're searching for alphanumeric chars starting from index 1, not exactly at index 1, so the regexp skips the question marks in the string and finds bc. It matched.

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@Blacksmoke16 I realize my explanation might have been insufficient. Thank you for the advice!

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String#match with a position argument starts searching for a match from that position. But not limited to that position. If you want the regex match to be anchored, please use the appropriate option: "a????bc".match(/[a-z]+/, 1, options: :anchored) # => nil

Thank you for your assistance!

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