拼接数组里的字符串

    NSArray *array = [NSString componentsSeparatedByString:@","];

我写的是所有的数据都以键值对的形式存在字典里
//取出所有字典
NSArray * arr = [addDicAll allKeys];
//排序
arr = [arr sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2){
        NSComparisonResult result = [obj1 compare:obj2];
        return result==NSOrderedDescending;
    }];
//根据key取出value
for (NSString * dicK in arr) {
        NSMutableArray * array = [NSMutableArray array];
        array = [addDicAll objectForKey:dicK];
        [arrayAll addObject:array];
    }
//拼接
NSString *sign = [arrayAll componentsJoinedByString:@","];