NSArray:固定長度陣列
使用固定一串資料給NSArray時,必須在陣列最後一個值放入nil,否則會發生錯誤。
範例:
NSArray *array = [ [ NSArray alloc ] initWithObjects:@”aa”,@”bbb”,nil];//宣告一陣列放入aa、bb字串
NSLog(@”array count==%d”,array.count);//印出陣列長度
for(int i = 0; i < array.count; i++){//取出陣列裡的字串並印出來
NSLog(@”i=%@”,[array objectAtIndex:i]);
}
[array release];//此陣列為暫存,且之後沒用到所以就將陣列從記憶體釋放
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NSMutableArray:動態陣列
可以不斷放入物件的陣列,陣列長度隨著放入的物件變動
靜態宣告陣列時,一樣必須在陣列最後一個值放入nil,否則會發生錯誤。
範例1 (動態新增):
NSMutableArray *array = [[NSMutableArray alloc]init];
[array addObject:@”aa”];
[array addObject:@”bbb”];
NSLog(@”array count==%d”,array.count);
for(int i = 0; i < array.count; i++){
NSLog(@”i=%@”,[array objectAtIndex:i]);
}
[array release];
範例2 (靜態放入值+動態新增)
NSMutableArray *array = [[NSMutableArray alloc]initWithObjects:@”cc”,@”ddd”,nil];
[array addObject:@”aa”];
[array addObject:@”bbb”];
NSLog(@”array count==%d”,array.count);
for(int i = 0; i < array.count; i++){
NSLog(@”i=%@”,[array objectAtIndex:i]);
}
[array release];
範例3 指定index放入物件,使用insertObject指定位置時,指定的位置必須是 (陣列長度 – 1) 以內的範例值
NSMutableArray *array = [[NSMutableArray alloc]initWithObjects:@”cc”,@”ddd”,nil];
[array addObject:@”aa”];
[array addObject:@”bbb”];
[array insertObject:@”aaaa” atIndex:4]; //在位置4放入 字串 aaaa
範例4:移除物件
移除指定位置物件
[array removeObjectAtIndex:4];
清除所有物件
[array removeAllObjects];
範例5:將數值放入陣列
int percentage = 40;
// 產生一個NSNumber物件,可以用signed or unsigned char, short int, int, long int, long long int, float, double or BOOL等基本型態產生物件
NSNumber *percentageObject = [NSNumber numberWithFloat:percentage];
//將NSNumber物件放入array
NSMutableArray *array = [[NSMutableArray alloc]init];
[array addObject:percentageObject];
//取出數值
[percentageObject intValue];
範例6:將指定位置的物件替換掉==>replaceObjectAtIndex:索引值(int) withObject:物件(id)
NSMutableArray *array = [[NSMutableArray alloc]initWithObjects:@”cc”,@”ddd”,nil];
[array addObject:@”aa”];
[array addObject:@”bbb”];
for(int i = 0; i < array.count; i++){
NSLog(@”i=%@”,[array objectAtIndex:i]);
}
[array replaceObjectAtIndex:2 withObject:@”111″];
for(int i = 0; i < array.count; i++){
NSLog(@”i=%@”,[array objectAtIndex:i]);
}
[array release];
NSDictionary及NSMutableDictionary(與java的Hashtable相似
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NSDictionary及NSMutableDictionary兩種,兩者合稱字典(dictionary),Mutable–善變的–表示可以變,NSDictionary則像是constant。NSMutableDictionary是NSDictionary的subClass。這就像一本字典,概念是(key, value),用key來搜尋出所需的value。
NSDictionary:
initWithObjectsAndKeys:
NSDictionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys: @”one”, [NSNumber numberWithInt: 1], @”two”,[NSNumber numberWithInt: 3], nil];
-(id) initWithObjectsAndKeys:(id) firstObject, ….
…..
第一個是firstObject的key,接著是secondObject、key,之後即為object、key的配對,直到出現nil為止。
注意:事實上nil一定出現在object的位置。若key是nil,會產生NSInvalidArgumentException。
NSMutableDictionary:
objectForKey:以下的key是由key = [objectOfNSEnumerator nextObject]; 產生的
[[[objectOfNSMutableDictionary objectForKey:key ] description] cString];
setObject: forKey:[mutable setObject:@”Tom” forKey:@”[email protected]”];
範例1: 利用NSEnumerator 取出NSMutableDictionary陣列裡所有的物件,
(1):取得所有value
NSMutableDictionary *taiStyle = [[NSMutableDictionary alloc]init];
//所有台型字串
[taiStyle setObject:[[NSNumber alloc] initWithInt:1] forKey:@”102″]; //
[taiStyle setObject:[[NSNumber alloc] initWithInt:1] forKey:@”103″]; //
NSEnumerator *enumerator = [taiStyle objectEnumerator];
id value;
while ((value = [enumerator nextObject])) {
NSLog(@”%i”,[((NSNumber*)value) intValue]);
}
(2):取得所有key
NSMutableDictionary *taiStyle = [[NSMutableDictionary alloc]init];
//所有台型字串
[taiStyle setObject:[[NSNumber alloc] initWithInt:1] forKey:@”102″]; //
[taiStyle setObject:[[NSNumber alloc] initWithInt:1] forKey:@”103″]; //
NSEnumerator *enumerator = [taiStyle keyEnumerator];
id key;
while ((key = [enumerator nextObject])) {
NSLog(@”%@”,((NSString*)key));
}
範例2:
(1)用key取出value物件,使用 valueForKey: key ,若使入的key找不到對應的key,會回傳nil
[[NSMutableDictionary *taiStyle = [[NSMutableDictionary alloc]init];
[taiStyle setObject:[[NSNumber alloc] initWithInt:1] forKey:@”102″]; //
[taiStyle setObject:[[NSNumber alloc] initWithInt:1] forKey:@”103″]; //
NSString *key = @”102″;
NSNumber *vlaue = [taiStyle valueForKey:key];
NSLog(@”%i”,[vlaue intValue] );
(2)指定key移除對應的key與value物件
[taiStyle removeObjectForKey:@”102″];//移除以@”102″字串當key的物件,key也會被移除