Object-C之词典(NSDictionary, NSMutableDictionary)

//程序启动界面显示之前会调用这个方法
//所以将语法代码添加在这里
- (void)viewDidLoad {
[super viewDidLoad];
//词典对象 类似java中map集合

//========1.不可变词典========
NSDictionary *dictionary=[ NSDictionary dictionaryWithObjectsAndKeys:@"jack", @"name", @"25",@"age", nil];

//大小
int len = [dictionary count];
NSLog(@"count=%d",len);

//遍历所有key
NSEnumerator *key= [dictionary keyEnumerator];

for (NSObject *obj in key) {
NSLog(@"key=%@",obj);//key=name ; key=age
}

//遍历所有value
NSEnumerator *value=[dictionary objectEnumerator];

for (NSObject *obj in value) {
NSLog(@"value=%@",obj);
}

//通过key找到value
NSObject *obj= [dictionary objectForKey:@"name"];
if (obj != nil) {
NSLog(@"通过KEY找到的value是: %@",obj);
}

//========2.可变词典========
NSMutableDictionary *mutableDictionary=[NSMutableDictionary dictionaryWithCapacity:10];

//设置值
[mutableDictionary setObject:@"jim" forKey:@"name"];
[mutableDictionary setObject:@"28" forKey:@"age"];

//通过key找到value
NSObject *object=[mutableDictionary objectForKey:@"age"];
if(object!=nil){
NSLog(@"通过KEY找到的value是: %@",object);
}

NSArray *arrayKey= [mutableDictionary allKeys];
NSArray *arrayValue = [mutableDictionary allValues];

}