title: Check if string contains occurence of digit
body: <p>I would like to check if a NSString contains each digit possible (0-9) more then 5 times. I do not need to know which digit or how many times, I simply want it to return TRUE or False for whether any of the digits are contained more then 5 times in the string. I would like it to be as efficient as possible.</p>
  
  <p>I have given it some thought and the long way of going about it would be to place all 10 digits (again 0-9) in an array and then loop through each digit comparing it to the string. If there are more than 5 matches within the string, place a flag that will return true. </p>
  
  <p>Can anyone tell me if there is a "better" or more efficient way of going about this problem?</p>
  
  <p>Thank you!</p>