The fourth bird questions

The fourth bird answers

• Regular expression: Match a string that contains no more than three consecutive Bs (without using negative lookahead)
• RegEx to span multiple lines
• Replace chars but exclude the word which is using it regex
• Removing everything except numbers inside braces and some characters
• RegExp: If-Clause for capturing group possible?
• Matching a word as a group in regular expressions
• Regex to extract (austrian) street housenumber/stairs/floor/door
• Find occurrences with regex and then only remove first character in matched expression
• How to find substrings flanked by a specific character and replace with text of the same length in R?
• Regex: finding words that end with the same letter the next word begins with