Shuffle NSMutableArray

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• the_stig Posts: 41Registered Users @

  July 2012 edited July 2012

  Best way to do that is just generate a random number then access the array item at that particular index.
  
  
  #include <stdlib.h> int numberOfItemsInArray = [arrayWithQuestions count]; //find out how many questions you have int randomNumber = arc4random() % numberOfItemsInArray; //generate a number less that or equal to the number of questions [arrayWithQuestion objectAtIndex:randomNumber]; //do with this what you will, this will return a random array item
  
  Note: This code is untested.
  
  
  
  
  

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• smithdale87 Posts: 4,447iPhone Dev SDK Supporter @ @ @ @ @

  July 2012

  This does not prevent you from selecting the same question multiple times, though.

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• djbrooks111 Posts: 62Registered Users @

  July 2012 edited July 2012

  I had wanted to do this as well and discovered how:
  
  randomPhrases is my NSMutableArray. The method shuffles the array and shows the array in the console once it is shuffled.

  -(void)shuffleQuestions {
      NSUInteger firstObject = 0;
      for (int i = 0; i < [randomPhrases count]; i++) {
          NSUInteger randomIndex = arc4random() % [randomPhrases count];
          [randomPhrases exchangeObjectAtIndex:firstObject withObjectAtIndex:randomIndex];
          firstObject += 1;
      }
      NSLog(@"Shuffled array:\n\n%@", randomPhrases);
  }

  Post edited by djbrooks111 on July 2012

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• the_stig Posts: 41Registered Users @

  July 2012

  smithdale87 said:

  This does not prevent you from selecting the same question multiple times, though.

  I need to learn to read the problem better. lol. If it's an NSMutableArray you can just remove that item once you're finished though yeah?
  
  

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• Vineesh Posts: 44Registered Users

  July 2012

  the_stig said:

  Best way to do that is just generate a random number then access the array item at that particular index.
  
  
  #include <stdlib.h> int numberOfItemsInArray = [arrayWithQuestions count]; //find out how many questions you have int randomNumber = arc4random() % numberOfItemsInArray; //generate a number less that or equal to the number of questions [arrayWithQuestion objectAtIndex:randomNumber]; //do with this what you will, this will return a random array item
  
  Note: This code is untested.
  
  
  
  
  

  It is repeating numbers.

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• djbrooks111 Posts: 62Registered Users @

  July 2012

  Here is my friendly reminder that I already posted the solution to properly shuffling a NSMutableArray in my above post

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