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I am trying to sort an array of NSDictionaries into an alphabatised array of arrays based of one of the NSDictionary valueForKey: first letters

effectively I want something that looks a little something like this

Array A // contains NSDictionaies with keyvalue MAF strings starting with A
 NSDictionary1
 NSDictionary2
 NSDictionary3
Array B // contains NSDictionaies with keyvalue MAF strings starting with B
 NSDictionary1
 NSDictionary2
 NSDictionary3
Array C // contains NSDictionaies with keyvalue MAF strings starting with C
 NSDictionary1
 NSDictionary2
 NSDictionary3
etc

So I have an array of Letters and inside each letter array I would like to have an Array of NSDictionary values that keyValue MAFs first letter should match.

So far I have an array of dictionaries that I have sorted like so

NSSortDescriptor *sortDescriptor;
        sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"MAF"
                                                      ascending:YES];
        NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
        sortedDictionaryArray = [arrayData sortedArrayUsingDescriptors:sortDescriptors]; // use this in cellforrow: and didselectrow:

        NSLog(@"%@", sortedDictionaryArray); // this gives me a sorted array of NSdictionaries based off their MAF keyvalue.

This is what the NSDicitonary looks like

HADM = 1;
ISLOT = 0;
ISVERT = 0;
MAF = "Yazot"; // keyvalue I am trying to work with.

Then I get stuck, I am not sure where to go from here. if anyone could help me understand how to create an NSArray of NSArrays NSDictionaries that would be great! hopefully I have explained what I am trying to do correctly, if you need any more details just let me know and I will supply.

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2 回答 2

2

此代码将首先使用分配给 key 的对象对您的字典数组进行排序@"MAF"。然后它将创建一个新的字典，它将为该字符串的每个第一个字母添加一个可变数组并将对象添加到其中。

NSArray *array = @[@{@"MAF": @"Yazot"}, @{@"MAF": @"Lorem"},@{@"MAF": @"Ipsum"}, @{@"MAF": @"Laura"},@{@"MAF": @"Isit"}];

NSArray *sortedArray = [array sortedArrayUsingComparator:^NSComparisonResult(NSDictionary *obj1, NSDictionary *obj2) {
    return [obj1[@"MAF"] compare:obj2[@"MAF"]];
}];

NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];

for (NSDictionary *dict in sortedArray) {
    NSString *firstLetter = [dict[@"MAF"] substringToIndex:1];

    if(![[dictionary allKeys] containsObject:firstLetter])
        dictionary[firstLetter] = [NSMutableArray array];

    [dictionary[firstLetter] addObject:dict];

}

如果您需要不区分大小写的字符串处理，“L”和“l”应该放在同一个数组中，做

NSArray *array = @[@{@"MAF": @"Yazot"}, @{@"MAF": @"Lorem"},@{@"MAF": @"Ipsum"}, @{@"MAF": @"Laura"},@{@"MAF": @"Isit"}];

NSArray *sortedArray = [array sortedArrayUsingComparator:^NSComparisonResult(NSDictionary *obj1, NSDictionary *obj2) {
    return [obj1[@"MAF"] caseInsensitiveCompare:obj2[@"MAF"]];
}];

NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];

for (NSDictionary *dict in sortedArray) {
    NSString *firstLetter = [dict[@"MAF"] substringToIndex:1];
    firstLetter = [firstLetter lowercaseString];
    if(![[dictionary allKeys] containsObject:firstLetter])
        dictionary[firstLetter] = [NSMutableArray array];

    [dictionary[firstLetter] addObject:dict];

}

字典结果

{
    i =     (
                {
            MAF = Ipsum;
        },
                {
            MAF = Isit;
        }
    );
    l =     (
                {
            MAF = Laura;
        },
                {
            MAF = Lorem;
        }
    );
    y =     (
                {
            MAF = Yazot;
        }
    );
}
于 2013-09-02T22:30:01.953 回答
1

我们可以从创建字典数组的字典开始。

NSMutableDictionary *dictsForFirstLetter = [[NSMutableDictionary alloc] init];

for (NSDictionary *dict in arrayData) {
    NSString *dictMAF = dict[@"MAF"];
    NSString *firstLetter = [[dictMAF substringToIndex:1] uppercaseString];
    NSMutableArray *dicts = dictsForFirstLetter[firstLetter];
    if (!dicts) {
        dicts = [[NSMutableArray alloc] init];
        dictsForFirstLetter[firstLetter] = dicts;
    }
    [dicts addObject:dict];
}

然后，您可以通过其 MAF 值的第一个字母检索字典数组：

NSArray *dicts = dictsForFirstLetter[@"Y"];

要从中获取按字母顺序排列的数组，您可以对字典的键进行排序并枚举它们：

NSMutableArray *alphabetizedDicts = [[NSMutableArray alloc] init];

NSArray *firstLetters = [dictsForFirstLetter allKeys];
NSArray *sortedFirstLetters = [firstLetters sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];

for (NSString *firstLetter in sortedFirstLetters) {
    NSArray *dicts = dictsForFirstLetter[firstLetter];
    [alphabetizedDicts addObject:dicts];
}
于 2013-09-02T22:30:04.750 回答