错误将NSarray分割成部分

好吧，所以我一直在通过一个与我正在尝试实现的密切匹配的示例，唯一的区别是，在他直接从数据库中调用他需要分段的数据等例子中，因为我已经有一个sortingNSArray的。

这是我正在工作的教程 – iPhone开发：创build本地联系人，如屏幕

我已经创build了一个方法，它捕获NSArray中的每个条目，并将这些结果放入一个基于alpha的NSDictionary（所以它们将成为A，B，C等的NSDictionary）

这是我的方法。

//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]; } } 

这是把每个值放入每个alpha部分，我希望有人可以帮助我，使得只有alpha部分build立，如果有一个值在数组中，然后只加载这些值到每个部分，而不是每部分。

Answer 1

这段代码可以做到这一点，并且比为每个字母过滤一次数组效率高得多。

 //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); 

请注意，arraysByLetter是一个字典，它包含一个数组，每个“首字母”存在于您的初始数据中。

—添加于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); 

输出如下：

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

Answer 2

看起来像你需要过滤sortedArray与每个字母的谓词。 像这样的东西…

 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]; }