知识点：
定义：字典（dictionary）是关键字及其定义的集合。
上代码：/** NSDictionary 不可变字典**/*dic1 = [[NSDictionary alloc] initWithObjectsAndKeys:@”wang”, @”name”, @33, @”age”, @”man”, @”gender”, nil] ;NSLog( @”%@”, dic1 ) ;NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:@”zhen”, @”name”, @22, @”age”, @”nv”, @”gender”, nil] ;NSLog( @”%@”, dic2 ) ;NSArray *keys = @[@”name”, @”age”, @”gender”] ;NSArray *values = @[@”wang”, @33, @”male”] ;//创建字典对象时两个数组元素个数必须一致NSDictionary *dic3 = [[NSDictionary alloc] initWithObjects:values forKeys:keys] ;NSLog( @”%@”, dic3 ) ;NSDictionary *dic4 = [NSDictionary dictionaryWithObjects:values forKeys:keys] ;NSLog( @”%@”, dic4 ) ;//通过count方法获取字典中键值对的个数NSLog( @”%ld”, [dic4 count] ) ;//获取字典中所有的键NSArray *allKeys = [dic4 allKeys] ;NSLog( @”%@”, allKeys ) ;//获取字典中所有的值NSArray *allValues = [dic4 allValues] ;NSLog( @”%@”, allValues ) ;//通过指定的键获取其在字典中对应的值id object = [dic4 objectForKey:@”age”] ;NSLog( @”%@”, object ) ;for (int i = 0 ; i < [dic4 count]; i++ ) {id key = [allKeys objectAtIndex:i] ;id value = [dic4 objectForKey:key] ;NSLog( @”%@”, value ) ;*result = [value isKindOfClass:[NSString class]] ? @”YES” : @”NO” ;NSLog( @”%@:%@–>%@”, key, value, result ) ;}//字典的语法糖形式（注意 ‘：’和‘，’是成对出现的）NSDictionary *dic5 = @{@”name”: @”wang”, @”age”: @33, @”gender”: @”man”} ;NSLog( @”%@”, dic5 ) ;/** NSMutableDictionary 可变 字典**///initWithDictionary 和 dictionaryWithDictionary 能将不可变字典变成可变字典NSMutableDictionary *dic6 = [[NSMutableDictionary alloc] initWithDictionary:dic5] ;NSLog( @”%@”, dic6 ) ;NSMutableDictionary *dic7 = [NSMutableDictionary dictionaryWithDictionary:dic5] ;NSLog( @”%@”, dic7 ) ;//两种初始化方式NSMutableDictionary *dic8 = [[NSMutableDictionary alloc] init] ;NSLog( @”%@”, dic8 ) ;NSMutableDictionary *dic9 = [NSMutableDictionary dictionary] ;NSLog( @”%@”, dic9 ) ;//增加 键值对[dic9 setObject:@”wang” forKey:@”name”] ;[dic9 setObject:@331 forKey:@”age”] ;[dic9 setObject:@”mam” forKey:@”gender”] ;NSLog( @”%@”, dic9 ) ;//修改已有键对应的值(注意：键若已存在就修改对应的值，，若不存在就添加此键值对)[dic9 setObject:@89 forKey:@”age”] ;NSLog( @”%@”, dic9 ) ;//根据指定键去删除对应的键值对[dic9 removeObjectForKey:@”age”] ;NSLog( @”%@”, dic9 ) ;//删除所有的键值对[dic9 removeAllObjects] ;NSLog( @”%@”, dic9 ) ;
这几年大多是昆明空运来的，
