iphone - 述語による NSDictionary のフィルタリング

Question

私は、いくつかのキーとその値の辞書を含む NSDictionary を使用しています。形式は、

{

"1" = {
        "key1" = "ss",
          "key2" = "rr",
          "name" = "nm"
     },
"2" = {
           "key1" = "tt",
          "key2" = "vv",
           "name" = "gf"
     },
"3" = {
           "key1" = "nm",
          "key2" = "vv",
           "name" = "gf"
     },
"4" = {
           "key1" = "tt",
          "key2" = "vv",
          "name" = "gf"
     },
}

NSPredicate を使用して、key1 を「tt」、key2 を「vv」にする必要があります。

Answer 1

NSDictionary *d = [NSDictionary dictionaryWithObjectsAndKeys:
                   [NSArray arrayWithObjects:@"a", @"b", @"c", nil], @"a",
                   [NSArray arrayWithObjects:@"b", @"c", @"a", nil], @"b",
                   [NSArray arrayWithObjects:@"c", @"a", @"b", nil], @"c",
                   [NSArray arrayWithObjects:@"a", @"b", @"c", nil], @"d",
                   nil];
NSPredicate *p = [NSPredicate predicateWithFormat:@"%@[SELF][0] == 'a'", d];
NSLog(@"%@", p);
NSArray *keys = [d allKeys];
NSArray *filteredKeys = [keys filteredArrayUsingPredicate:p];
NSLog(@"%@", filteredKeys);
NSDictionary *matchingDictionary = [d dictionaryWithValuesForKeys:filteredKeys];
NSLog(@"%@", matchingDictionary);

これは本当に役に立ちます。

Answer 2

keysOfEntriesPassingTestの方法が使えますNSDictionary。

例えば。

NSSet *keys = [dict keysOfEntriesPassingTest:^BOOL(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
NSDictionary *object =(obj); 
return ([@"tt" isEqualToString:object[@"key1] &&[@"vv"isEqualToString:object[@"key2"]);
}];

参考：Apple Doc