Using Regex to return the first N words in a string

8 Comments

• Why not just look for the Nth single space?
  

• Why do you need the stringbuilder? Just return the first match from..
  
  
  
  Regex.Match(s, "(\w+\s+){5}").ToString().Trim
  
  
  
  given input of...
  
  
  
  "this is word four five six seven eight nine ten eleven twelve thirteen!"
  
  
  
  returns first match of..
  
  
  
  "this is word four five"
  

• Jeff: Excellent idea!
  
  that works just as well :)
  

• And if Jeff's version doesn't have any matches, you'd just spit out the original string, on the assumption that it didn't have at least N words.
  

• If you replace spaces with word boundries then you don't have to Trim(), and punctuation won't break the function:
  
  
  
  ^(\w+\b.*?){4}
  
  
  
  Also, this matches only the first set, so theoretically it may be faster?
  

• Oh yeah, we definitely should have used "^" so we don't get multiple matches.
  

• I have a function that checks if string contains a specific pattern, I do it by using string.IndexOf method. Using regex seem to be more elegant solution for this. My question is if using regex is more efficient way for this problem?
  

• What if you had a sentence, and wanted to just return the nth word from a sentence? Like the third or fourth word