CODEWITHSUNDEEP
regexitalic
Vid
Vid

Reputation: 173

Regex for matching predefined rules for italic text formatting

I'm trying to write a regex for matching user input that will be turned into italic format using markdown.

In the string i need to find the following pattern: an asterisk followed by any kind of non-whitespace character and ending with any kind of non-whitespace character followed by an asterisk.

So basically: substring *substring substring substring* substring should spit out *substring substring substring*.

So far I came up only with /\*(?:(?!\*).)+\*/, which matches everything between two asterisks, but it doesn't take into consideration whether the substring between asterisks starts or end with whitespace - which it shouldn't.

Thank you for your input! :)

Upvotes: 2

Views: 1589

Answers (2)

Sachin Chillal
Sachin Chillal

Reputation: 531

/(?<!\*)\*(?![*\s])(?:[^*]*[^*\s])?\*(?!\*)/gim

To match only italic text

**Not matches this**
*Not this one also**
**Not again*
*It's will match*

Thanks to Ryszard Czech and Vid

Upvotes: 2

Ryszard Czech
Ryszard Czech

Reputation: 18611

Use

\*(?![*\s])(?:[^*]*[^*\s])?\*

See regex proof.

EXPLANATION

--------------------------------------------------------------------------------
  \*                       '*'
--------------------------------------------------------------------------------
  (?!                      look ahead to see if there is not:
--------------------------------------------------------------------------------
    [*\s]                    any character of: '*', whitespace (\n,
                             \r, \t, \f, and " ")
--------------------------------------------------------------------------------
  )                        end of look-ahead
--------------------------------------------------------------------------------
  (?:                      group, but do not capture (optional
                           (matching the most amount possible)):
--------------------------------------------------------------------------------
    [^*]*                    any character except: '*' (0 or more
                             times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
    [^*\s]                   any character except: '*', whitespace
                             (\n, \r, \t, \f, and " ")
--------------------------------------------------------------------------------
  )?                       end of grouping
--------------------------------------------------------------------------------
  \*                       '*'

Upvotes: 3

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