Replace strings with both regular and special characters with whitespace in between

Question

I'm looking for how to handle strings with both regular and special characters with whitespace in between.

text = 'You got a Check +'

lookup_term = check +

replace_with_term = 'check+'

Final product I'm looking for is you got a check+

I am currently using text.downcase.gsub(/\blookup_term\b/, replace_with_term) to handle lookup_term with regular characters, but I can't seem to fingure out how to handle the combo of regular expression + whitespace + special character.

Answer 1

You may use

text.downcase.gsub(/(?<!\w)#{Regexp.escape(lookup_term)}(?!\w)/, replace_with_term)

If you do not really want to get the string turned into lowercase, but just want case insensitive matching, use the /i modifier and remove .downcase:

text.gsub(/(?<!\w)#{Regexp.escape(lookup_term)}(?!\w)/i, replace_with_term)

See the Ruby demo online.

The resulting regex will look like /(?<!\w)check\ \+(?!\w)/, see Rubular demo.

Note that \b meaning is context-dependent, and matches an empty space (a location)

1. Before the first character in the string, if the first character is a word character.
2. After the last character in the string, if the last character is a word character.
3. Between two characters in the string, where one is a word character and the other is not a word character.

The (?<!\w)check\ \+(?!\w) pattern contains unambiguous word boundaries, they always match the same way:

• (?<!\w) - a left-hand word boundary, requires a start of string position or any non-word character immediately to the left of the current location
• check\ \+ - check, space and +
• (?!\w) - a right-hand word boundary, requires an end of string position or any non-word character immediately to the right of the current location.