Elton's Blog

NSArray *array = [NSArray arrayWithObjects: 
    @"Hefeweizen", @"IPA", @"Pilsner", @"Stout", nil];
 
NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:
  array, @"array", @"Stout", @"dark", @"Hefeweizen", @"wheat", @"IPA", 
  @"hoppy", nil];
 
// 得到documents directory的路径
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, 
  NSUserDomainMask, YES);
if ([paths count] > 0)
{
  // Array的保存路径
  NSString  *arrayPath = [[paths objectAtIndex:0] 
      stringByAppendingPathComponent:@"array.out"];
 
  // dictionary的保存路径
  NSString  *dictPath = [[paths objectAtIndex:0] 
      stringByAppendingPathComponent:@"dict.out"];
 
  // 保存array
  [array writeToFile:arrayPath atomically:YES];
 
  // 保存dictionary
  [dictionary writeToFile:dictPath atomically:YES];
 
  // 从文件中读取回来
  NSArray *arrayFromFile = [NSArray arrayWithContentsOfFile:arrayPath];
  NSDictionary *dictFromFile = [NSDictionary dictionaryWithContentsOfFile:dictPath];
 
  for (NSString *element in arrayFromFile) 
    NSLog(@"Beer: %@", element);
 
  for (NSString *key in dictFromFile) 
    NSLog(@"%@ Style: %@", key, [dictionary valueForKey:key]); 
}

NSMutableArray * tree = [NSMutableArray array];
NSDictionary   * p = nil;   // parent
NSDictionary   * c = nil;   // child
NSNumber       * n = nil;   // value
int i;
 
for ( i = 0; i < 10; i++ )
{
n = [NSNumber numberWithInt: i];
c = [NSDictionary dictionaryWithObject:n forKey: @"someKey"];
p = [NSDictionary dictionaryWithObject: c forKey: @"storage"];
[tree addObject: p];
}
 
NSLog (@"%@", tree);
// here's the important part!
NSArray * justValues;
justValues = [tree valueForKeyPath: @"storage.someKey"];
NSLog (@"%@", justValues);

NSLog (@"%@", tree);
(
{storage = {someKey = 0; }; },
{storage = {someKey = 1; }; },
{storage = {someKey = 2; }; },
{storage = {someKey = 3; }; },
{storage = {someKey = 4; }; },
{storage = {someKey = 5; }; },
{storage = {someKey = 6; }; },
{storage = {someKey = 7; }; },
{storage = {someKey = 8; }; },
{storage = {someKey = 9; }; }
)

NSArray * justValues;
justValues = [tree valueForKeyPath: @"storage.someKey"];
NSLog (@"%@", justValues);
(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)

NSString *string = @"white:black:blue:red";
NSArray *aArray = [string componentsSeparatedByString:@":"];

string = [aArray componentsJoinedByString:@","];