这个最典型的就是电话本，然后根据A－Z分组, 当然很多例子，不过现在发现一个很简洁易懂的：
1. 准备数据，定义一个dictionary来显示所有的内容，这个dictionary对应的value全是数组
也就是：
A －> A1, A2...
B -> B1, B2...
...
NSMutableDictionary *sections;
2. 创建所有的Keys
BOOL found;// Loop through the books and create our keysfor (NSDictionary *book in self.books) //self.books 就是包含NSDictionary的数组{NSString *c = [[book objectForKey:@"title"] substringToIndex:1];found = NO;for (NSString *str in [self.sections allKeys]){if ([str isEqualToString:c]){found = YES;}}if (!found){[self.sections setValue:[[NSMutableArray alloc] init] forKey:c];}}
3. 把Key对应的空数组填满，这个很简单应该能看懂
for (NSDictionary *book in self.books){[[self.sections objectForKey:[[book objectForKey:@"title"] substringToIndex:1]] addObject:book];}
4. 下面就排序
for (NSString *key in [self.sections allKeys]){[[self.sections objectForKey:key] sortUsingDescriptors:[NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"title" ascending:YES]]];}
5. 有了上面的方法之后，就执行UITableView必须的方法
#pragma mark -
#pragma mark Table view data source- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{return [[self.sections allKeys] count];
}- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{return [[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:section];
}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{return [[self.sections valueForKey:[[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:section]] count];
}- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {return [[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {static NSString *CellIdentifier = @"Cell";UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];if (cell == nil) {cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];}NSDictionary *book = [[self.sections valueForKey:[[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:indexPath.section]] objectAtIndex:indexPath.row];cell.textLabel.text = [book objectForKey:@"title"];cell.detailTextLabel.text = [book objectForKey:@"description"];return cell;
}差不多了，这个是我见过最简洁的例子了。
参考：http://www.icodeblog.com/2010/12/10/implementing-uitableview-sections-from-an-nsarray-of-nsdictionary-objects/
