Change a dictionary's all value to string

Question

I want to change the Dictionary's all value to String, how to do with it?

Such as:

{   @"a":"a", 
    @"b":2, 
    @"c":{
      @"c1":3,
      @"c2":4
    }
}

I want convert to :

{   @"a":"a", 
    @"b":"2", 
    @"c":{
      @"c1":"3",
      @"c2":"4"
    }
}

How to do with it? I think all the day.

If I use below method to traverse the dictionary values:

NSArray *valueList = [dictionary allValues];

for (NSString * value in valueList) {
    // change the value to String
}

If the value is a dictionary, how about it?

So, someone can help with that?

Answer 1

You could do this with a recursive method, it changes all NSNumber values to NSString and calls itself for nested dictionaries. Since a dictionary cannot be mutated while being enumerated a new dictionary is created and populated:

- (void)changeValuesOf:(NSDictionary *)dictionary result:(NSMutableDictionary *)result
{
    for (NSString *key in dictionary) {
        id value = dictionary[key];
        if ([value isKindOfClass: [NSDictionary class]]) {
            NSMutableDictionary * subDict = [NSMutableDictionary dictionary];
            result[key] = subDict;
            [self changeValuesOf:value result:subDict];
        } else if ([value isKindOfClass: [NSNumber class]]) {
            result[key] = [NSString stringWithFormat:@"%@", value];
        } else {
            result[key] = value;
        }
    }
}

NSDictionary *dictionary = @{@"a": @"a", @ "b":@2, @"c": @{@"c1": @3,  @"c2":@4 }};
NSMutableDictionary *result = [NSMutableDictionary dictionary];
[self changeValuesOf:dictionary result:result];
NSLog(@"%@", result);