Question

I’ve got a NSDictionary and I’d like put all of it’s objects and keys into a NSString, so that I can finally display them in a label like this:

key1: object1

key2: object2

key3: object3

… …

Any ideas?

Answer 1

Build the string and then set it to the labels text.

NSMutableString *myString = [[NSMutableString alloc] init];

[dictionary enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
    [myString appendFormat:@"%@ : %@\n", key, obj];
}];

self.label.text = myString;

Note

The docs (String Programming Guide) for the %@ format specifier state:

%@
Objective-C object, printed as the string returned by descriptionWithLocale: if available, or description otherwise. Also works with CFTypeRef objects, returning the result of the CFCopyDescription function.

So if these are your own custom objects in the dictionary you will most likely need to override the description method to provide more meaningful output

Update

You mention that you need your output sorted by keys – dictionaries are not ordered so you will have to do it differently – this example assumes that your keys are strings

NSArray *sortedKeys = [[dictionary allKeys] sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];

NSMutableString *myString = [[NSMutableString alloc] init];

for (NSString *key in sortedKeys) {
    [myString appendFormat:@"%@ : %@\n", key, [dictionary objectForKey:key]];
}

self.label.text = myString;