How to get the first N words from a NSString in Objective-C?

Question

What\'s the simplest way, given a string:

NSString *str = @\"Some really really long string is here and I just want the first 10 words, for example\";
         


        

Answer 1

While Barry Wark's code works well for English, it is not the preferred way to detect word breaks. Many languages, such as Chinese and Japanese, do not separate words using spaces. And German, for example, has many compounds that are difficult to separate correctly.

What you want to use is CFStringTokenizer:

CFStringRef string; // Get string from somewhere
CFLocaleRef locale = CFLocaleCopyCurrent();

CFStringTokenizerRef tokenizer = CFStringTokenizerCreate(kCFAllocatorDefault, string, CFRangeMake(0, CFStringGetLength(string)), kCFStringTokenizerUnitWord, locale);

CFStringTokenizerTokenType tokenType = kCFStringTokenizerTokenNone;
unsigned tokensFound = 0, desiredTokens = 10; // or the desired number of tokens

while(kCFStringTokenizerTokenNone != (tokenType = CFStringTokenizerAdvanceToNextToken(tokenizer)) && tokensFound < desiredTokens) {
  CFRange tokenRange = CFStringTokenizerGetCurrentTokenRange(tokenizer);
  CFStringRef tokenValue = CFStringCreateWithSubstring(kCFAllocatorDefault, string, tokenRange);

  // Do something with the token
  CFShow(tokenValue);

  CFRelease(tokenValue);

  ++tokensFound;
}

// Clean up
CFRelease(tokenizer);
CFRelease(locale);