Iphone 从NSArray取同一生日的名字

我有一系列的字典，以生日和名字为键。我想检索具有相同生日的名称的值

    for (NSDictionary *contactDict in contactList) {
            NSString *birthdayStr = [contactDict objectForKey:BIRTHDAY_KEY];
}

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我应该怎么做才能得到相同生日的名字数组

这就是你要找的吗

for (NSDictionary *contactDict in contactList) {
    NSString *birthdayStr = [contactDict objectForKey:BIRTHDAY_KEY];

    // indexes of all array objects with same birthday:
    NSIndexSet *matching = [contactList indexesOfObjectsPassingTest:^BOOL(NSDictionary *contactDict, NSUInteger idx, BOOL *stop) {
        return [[contactDict objectForKey:BIRTHDAY_KEY] isEqualToString:birthdayStr];
    }];

    NSArray *matchingNames = [[contactList objectsAtIndexes:matching] valueForKey:NAME_KEY];
    NSLog(@"%@", matchingNames);
}

或者，如果每个不同的生日只需要一个名称数组：

// Set of all distinct birthdays:
NSSet *allBirthdays = [NSSet setWithArray:[contactList valueForKey:BIRTHDAY_KEY]];

for (NSString *birthdayStr in allBirthdays) {
    NSLog(@"birthday: %@", birthdayStr);

    NSIndexSet *matching = [contactList indexesOfObjectsPassingTest:^BOOL(NSDictionary *contactDict, NSUInteger idx, BOOL *stop) {
        return [[contactDict objectForKey:BIRTHDAY_KEY] isEqualToString:birthdayStr];
    }];

    NSArray *matchingNames = [[contactList objectsAtIndexes:matching] valueForKey:NAME_KEY];
    NSLog(@"names: %@", matchingNames);
}

示例数据的输出：

---

这就是你要找的吗

for (NSDictionary *contactDict in contactList) {
    NSString *birthdayStr = [contactDict objectForKey:BIRTHDAY_KEY];

    // indexes of all array objects with same birthday:
    NSIndexSet *matching = [contactList indexesOfObjectsPassingTest:^BOOL(NSDictionary *contactDict, NSUInteger idx, BOOL *stop) {
        return [[contactDict objectForKey:BIRTHDAY_KEY] isEqualToString:birthdayStr];
    }];

    NSArray *matchingNames = [[contactList objectsAtIndexes:matching] valueForKey:NAME_KEY];
    NSLog(@"%@", matchingNames);
}

或者，如果每个不同的生日只需要一个名称数组：

// Set of all distinct birthdays:
NSSet *allBirthdays = [NSSet setWithArray:[contactList valueForKey:BIRTHDAY_KEY]];

for (NSString *birthdayStr in allBirthdays) {
    NSLog(@"birthday: %@", birthdayStr);

    NSIndexSet *matching = [contactList indexesOfObjectsPassingTest:^BOOL(NSDictionary *contactDict, NSUInteger idx, BOOL *stop) {
        return [[contactDict objectForKey:BIRTHDAY_KEY] isEqualToString:birthdayStr];
    }];

    NSArray *matchingNames = [[contactList objectsAtIndexes:matching] valueForKey:NAME_KEY];
    NSLog(@"names: %@", matchingNames);
}

示例数据的输出：

---

你说同样的生日是什么意思？比如，当你有一个生日字符串时，得到它对应的所有名字？或者得到一个生日在某处重复的所有名字的列表？假设Dict的值为1/12/13，a；1/12/13，B；2/12/13，C。那么我需要一个数组，用于1/12/13和2/12/13，作为（A，B）和C。你说的相同的生日是什么意思？比如，当你有一个生日字符串时，得到它对应的所有名字？或者得到一个生日在某处重复的所有名字的列表？假设Dict的值为1/12/13，a；1/12/13，B；2/12/13，C。然后我需要一个1/12/13和2/12/13的数组作为（A，B）和C。Thnx martin。这正是我要找的…多谢了Hnx martin。这正是我要找的…多谢了