Question

如果我是NSLOG（）我正在尝试搜索的数组，我会得到这个...

(
    {
    id = 101323790;
    "screen_name" = AmyBurnett34;
},
    {
    id = 25073877;
    "screen_name" = realDonaldTrump;
},
    {
    id = 159462573;
    "screen_name" = ecomagination;
},
    {
    id = 285234969;
    "screen_name" = "UCB_Properties";
},
    {
    id = 14315150;
    "screen_name" = MichaelHyatt;
}
)

这很好但我需要做的是能够有一个方法让我输入一个id然后它返回匹配的screen_name作为NSString。我怎么能这样做是调用数组。

我认为NSPredicate是我正在寻找的但我不确定......

NSArray *twitterInfo;

Answer 1

是的，NSPredicate就是你想要的。像这样：

NSString yourID; // assume this contains the id you want
NSPredicate *pred = [NSPredicate predicateWithFormat:@"id = %@", yourID];
NSString *screenName = [[[twitterInfo filteredArrayUsingPredicate:pred] lastObject] objectForKey:@"screen_name"];

Answer 2

我偏爱使用块的枚举（比谓词更容易理解： - ）：

NSInteger desiredID = ...;
__block NSString *userName;

NSString *name = [twitterInfo enumerateObjectsUsingBlock:^(NSDictionary *dict, NSUInteger idx, BOOL *stop)
{
  NSInteger theID = [[dict objectForKey:@"id"] integerValue];
NSLog(@"Check ID %d against %d", theID, desiredID); // just to see its working
  if(theID == desiredID) {
    userName = [dict objectForKey:@"screen_name"];
    *stop = YES;
  }
} ];

如果userName在此末尾为nil，则找不到id。

搜索NSArray的NSDiction

2 个答案: