Question

Hi i want regular expression to find one or more than one substrings inside big string match some criteria like.

   "I have done my best to document all the [switches] and characters that I can  locate.Regular expressions [allow] you to group like [parts] of the substring into"

the result should be like these substrings

         switches,allow,parts

and in this case

      "I have done my best to document all the [switches] and character.

result should be the only “switches”

Thanks in advance.

Answer 1

You need String#scan:

str = "I have done my best to document all the [switches] and characters that I can  locate.Regular expressions [allow] you to group like [parts] of the substring into"
str.scan /\[.+?\]/   # => ["[switches]", "[allow]", "[parts]"]
# or use lookahead and lookbehind pattern
str.scan /(?<=\[).+?(?=\])/ # => ["switches", "allow", "parts"]

The Regexp will match any chars between ‘[‘ and ‘]’. The pattern .+? means NOT do this thing greedy. When a “]” is matched, this part is over. Otherwise, if we use [.*] , the matching will return [switches……parts].