Generate a random alphanumeric String in ios

Question

How to Generate a random non-repeated(without repeating same alphabet) alphanumeric string from a given String in ios?

possible duplicate of [Generate a random alphanumeric string in cocoa](http://stackoverflow.com/questions/2633801/generate-a-random-alphanumeric-string-in-cocoa) — Wain, Oct 28 '13 at 12:53
how do you mean _non-repeated_? are you looking for unique string identifier in runtime? — holex, Oct 28 '13 at 13:01

score 4 · Accepted Answer · answered Oct 28 '13 at 13:07

The following function will take a string and randomise it, usually each character from the input string only once:

- (NSString *)randomizeString:(NSString *)str
{
    NSMutableString *input = [str mutableCopy];
    NSMutableString *output = [NSMutableString string];

    NSUInteger len = input.length;

    for (NSUInteger i = 0; i < len; i++) {
        NSInteger index = arc4random_uniform((unsigned int)input.length);
        [output appendFormat:@"%C", [input characterAtIndex:index]];
        [input replaceCharactersInRange:NSMakeRange(index, 1) withString:@""];
    }

    return output;
}

score 3 · Answer 2 · edited Jul 20 '15 at 22:56

-(NSString *)randomStringWithLength: (int) len 

{

  NSString *letters = @"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

   NSMutableString *randomString = [NSMutableString stringWithCapacity: len];

    for (int i=0; i<len; i++) 
{

         [randomString appendFormat: @"%C", [letters characterAtIndex: arc4random() % [letters length]]];
    }

    return randomString;
}`

Generate a random alphanumeric String in ios

2 Answers2