錯誤劈裂的NSArray段

Question

好了，我已經經歷了一個接近我努力才達到爲例進行了工作，是在例子中，他是直接從他的數據庫調用，唯一的區別，他需要對數據進行切片等。因爲我已經有一個排序的NSArray。

這是我工作過的教程 - 我已經創建了被捕獲在NSArray的每個條目，並把這些結果爲基礎的NSDictionary一個α（所以他們將是一個一個的NSDictionary一個方法iPhone Development: Creating Native Contacts like screen

， B，C ...等）

這裏是我的方法。

//method to sort array and split for use with uitableview Index 
- (IBAction)startSortingTheArray:(NSMutableArray *)arrayData 
{ 
    //Sort incoming array alphabetically 
    //sortedArray = [arrayData sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)]; 
    [self setSortedArray:[arrayData sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)]]; 

    arrayOfCharacters = [[NSMutableArray alloc]init]; 
    objectsForCharacters = [[NSMutableDictionary alloc]init]; 

    for(char c='A';c<='Z';c++) 
    { 

     if([sortedArray count] >0) 
     { 
      [arrayOfCharacters addObject:[NSString stringWithFormat:@"%c",c]]; 
      [objectsForCharacters setObject:sortedArray forKey:[NSString stringWithFormat:@"%c",c]]; 
      NSLog(@"%@", objectsForCharacters); 
     } 
     [sortedArray release]; 


    //Reloads data in table 
    [self.tableView reloadData]; 
    } 
} 

這是把每一個值到每個字母部分，我希望有人能幫助我，使得它如此，如果有數組爲它的值只允許使用字母部分是建立..然後只加載那些值分配到每個部分，而不是每個部分。

Answer 1

這段代碼將做到這一點，將是比每個字母濾波陣列一旦有效得多。

//Sort incoming array alphabetically so that each sub-array will also be sorted. 
NSArray *sortedArray = [arrayData sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)]; 

// Dictionary will hold our sub-arrays 
NSMutableDictionary *arraysByLetter = [NSMutableDictionary dictionary]; 

// Iterate over all the values in our sorted array 
for (NSString *value in sortedArray) { 

    // Get the first letter and its associated array from the dictionary. 
    // If the dictionary does not exist create one and associate it with the letter. 
    NSString *firstLetter = [value substringWithRange:NSMakeRange(0, 1)]; 
    NSMutableArray *arrayForLetter = [arraysByLetter objectForKey:firstLetter]; 
    if (arrayForLetter == nil) { 
     arrayForLetter = [NSMutableArray array]; 
     [arraysByLetter setObject:arrayForLetter forKey:firstLetter]; 
    } 

    // Add the value to the array for this letter 
    [arrayForLetter addObject:value]; 
} 

// arraysByLetter will contain the result you expect 
NSLog(@"Dictionary: %@", arraysByLetter); 

注意arraysByLetter是一個包含每個存在於你的初始數據「第一個字母」一個陣列的字典。

---增加了關於2011-09-23 ---

[sortedArray removeAllObjects]; 
NSArray *sortedKeys = [arraysByLetter.allKeys sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)]; 

for (NSString *key in sortedKeys) { 
    [sortedArray addObject:key]; 
    [sortedArray addObjectsFromArray: [arraysByLetter objectForKey:key]]; 
} 

NSLog(@"Sorted Array: %@", sortedArray); 

輸出如下：

C, 
Computer, 
H, 
Helene, 
Hello, 
J, 
Jules, 
W, 
World 

Answer 2

看起來你需要爲每個字母謂詞來過濾sortedArray。事情是這樣的......

for(char c='A';c<='Z';c++) { 
    NSPredicate *predicate = 
    [NSPredicate predicateWithFormat:@"SELF beginswith[c] '%c'", c]; 
    NSArray *objectsBeginningWithCurrentLetter = [array filteredArrayUsingPredicate:predicate]; 

    if([sortedArray count] >0) 
    { 
     [arrayOfCharacters addObject:[NSString stringWithFormat:@"%c",c]]; 
     if ([objectsBeginningWithCurrentLetter count] > 0) { 
      [objectsForCharacters setObject:objectsBeginningWithCurrentLetter forKey:[NSString stringWithFormat:@"%c",c]]; 
      NSLog(@"%@", objectsForCharacters); 
     } 
    } 
    [sortedArray release]; 


//Reloads data in table 
[self.tableView reloadData]; 
}