NSMutableArray with random strings

Question

How can I get 5 random strings in array? I tried this:

stringsArray = [[NSMutableArray alloc]init];
int string_lenght = 10;
NSString *symbols = @"ABCDEFGHIJKLMNOPQRSTUWXYZabcdefghijklmnopqrstuvwxyz";
NSMutableString *randomString = [NSMutableString stringWithCapacity:string_lenght];

for (int y = 0; y<5; y++) {
    for (int i = 0; i<string_lenght; i++) {
        [randomString appendFormat:@"%C", [symbols characterAtIndex:random()%[symbols length]]];
    }
    stringsArray = [NSMutableArray arrayWithObject:randomString];
}

But after I run this, all I have is one long random string!

wattson12 · Accepted Answer · 2013-11-07 16:45:40Z

1

you are setting the strings array each time, change

stringsArray = [NSMutableArray arrayWithObject:randomString];

to

[stringsArray addObject:randomString];

and you should move the randomString initialisation into the for loop, or you will be appending new random characters to the same string

answered Nov 7, 2013 at 16:45

wattson12

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Comments

James Webster · Accepted Answer · 2013-11-07 16:45:29Z

0

You almost had it. I think this should work, but I haven't tested it.

stringsArray = [[NSMutableArray alloc] init];
int string_length = 10;
NSString *symbols = @"ABCDEFGHIJKLMNOPQRSTUWXYZabcdefghijklmnopqrstuvwxyz";

for (int y = 0; y < 5; y++) 
{
    //Allocate a new "randomString" object each time, or you'll just add to the old one
    NSMutableString *randomString = [NSMutableString stringWithCapacity:string_length];
    for (int i = 0; i < string_length; i++) 
    { 
        char c = [symbols characterAtIndex:random() % [symbols length]];
        [randomString appendFormat:@"%c", c];
    }

    //Add the object to the array instead of replacing the entire array
    [stringsArray addObject:randomString];
}

answered Nov 7, 2013 at 16:45

James Webster

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1 Comment

James Webster Over a year ago

You're welcome. =] Don't forget to mark an answer as correct when it helps you and optionally upvote it.

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