如何在具有相同键的其他值之间获取特定值

Question

我的JSON响应是这样的：

{
   "results" : [
      {
         "address_components" : [
            {
               "long_name" : "285",
               "short_name" : "285",
               "types" : [ "street_number" ]
            },
            {
               "long_name" : "Bedford Ave",
               "short_name" : "Bedford Ave",
               "types" : [ "route" ]
            },
            {
               "long_name" : "Williamsburg",
               "short_name" : "Williamsburg",
               "types" : [ "neighborhood", "political" ]
            },
            {
               "long_name" : "Brooklyn",
               "short_name" : "Brooklyn",
               "types" : [ "sublocality", "political" ]
            },

我需要获取键long_name的最后一个值

{
                   "long_name" : "Brooklyn",//i need to get this "Brooklyn"
                   "short_name" : "Brooklyn",
                   "types" : [ "sublocality", "political" ]
                },

尽管有很多值具有相同的键long_name，我如何才能获得该值

NSArray *resultsArray = [responseDict objectForKey:@"results"];//what to do next?

Answer 1

[[[[[resultsArray objectAtIndex:0] valueForKey:@"address_components"] valueForKey:@"long_name"] lastObject];

分解：

// get array of address components
[[resultsArray objectAtIndex:0] valueForKey:@"address_components"]

// calling this on array will get you long_name values from ALL elements
...] valueForKey:@"long_name"]

// finally grab the last element long_name array
...] lastObject];

等效项为：

[[[[resultsArray objectAtIndex:0] valueForKey:@"address_components"] lastObject] valueForKey:@"long_name"];

分解：

// get array of address components
[[resultsArray objectAtIndex:0] valueForKey:@"address_components"]

// get last dictionary
...] lastObject]

// get long_name from last dictionary
...] valueForKey:@"long_name"]