1. 字典类型的常用处理
//---------------不可变字典
//1.字典的创建
NSArray *array1 = [NSArray arrayWithObjects:@"zhangsan",@"zhangfei",nil];
NSArray *array2 = [NSArray arrayWithObjects:@"lisi",@"liping", nil];
//第一元素：key：@“zhang" value:array1
//第二元素：key: @"li: value:array2
NSDictionary *dic1 = [[NSDictionary alloc] initWithObjectsAndKeys:array1,@"zhang",array2,@"li", nil];
NSUInteger count = dic1.count; //字典元素个数
NSLog(@"count:%d",count);
//创建字典时初始化一个元素
NSDictionary *dic2 = [NSDictionary dictionaryWithObject:array1 forKey:@"zhang"];
NSLog(@"dic2 = %@",dic2);
//2.获取字典中所有的key
NSArray *allKeys = [dic1 allKeys]; //dic1.allKeys.
NSLog(@"allKeys= %@",allKeys);
//3.获取字典中所有的value
NSArray *allValues = [dic1 allValues];
NSLog(@"allValues = %@",allValues);
//4.通过key取得value
NSArray *array3 = [dic1 objectForKey:@"zhang"];
NSLog(@"array3 = %@",array3);
//------------字典中优化的方法
NSDictionary *dic3 = @{@"zhang": array1,@"li":array2};
NSLog(@"dic3 = %@",dic3);
//取value的语法：字典［”key“］
NSArray *array4 = dic3[@"zhang"]; //等价于：NSArray *array3 = [dic3 objectForKey:@"zhang"];
NSLog(@"array4 = %@",array4);
//--------------可变字典
//1.创建一个可变字典
NSMutableDictionary *md1 = [[NSMutableDictionary alloc] initWithCapacity:3];
//2.添加元素
[md1 setObject:array1 forKey:@"zhang"];
[md1 setObject:array2 forKey:@"li"];
NSLog(@"md1 = %@",md1);
//将字典dic1 中所有的元素添加到md1字典中
[md1 addEntriesFromDictionary:dic1];
NSLog(@"md1 = %@",md1);
// [md1 setObject:@"zhangsan" forKey:@"zhang"]; //如果添加相同的key,会将原来的Value覆盖掉
//3.删除（根据key删除元素）
[md1 removeObjectForKey:@"zhang"];
NSLog(@"md1 = %@",md1);
//删除所有元素（清空）
//[md1 removeObjects];
// //根据多个key删除对应的多个元素
// [md1 removeObjectsForKeys:@[@"zhang",@"li"]];
// NSLog(@"md1 = %@",md1);
//---------------------遍历字典
//1.快速遍历
for (NSString *key in md1) {
NSArray *name = [md1 objectForKey:key];
NSLog(@"快速遍历：key = %@,value = %@",key,name);
}
//2.普通遍历
NSArray *allKeys2 = [md1 allKeys];
for (int i = 0; i<allKeys.count - 1; i++) {
NSString *key = allKeys2[i];
NSArray *name = md1[key];
NSLog(@"普通遍历：key = %@,value = %@",key,name);
}