[学习交流] 字典类

//字典是以键值对的形式来存储数据 key value
int main(int argc, const char * argv[])
{
@autoreleasepool {
//1.创建字段,不可变的
NSDictionary * dic = [NSDictionary dictionaryWithObjectsAndKeys:@"xiaozhe",@"name", nil];
NSLog(@"dic %@",dic);
//2.快捷创建方式
NSDictionary * dic2 = @{ @"one":@"1",@"two":@"2"};
NSLog(@"dic2 %@",dic2);
//3.字典中可以存任意数据类型
// 字典的顺序不是自然顺序
NSArray * array = @[@"one",@"two"];
NSDictionary * dic3 = @{
@"one":@"1",
@"num":[NSNumber numberWithInt:10],
@"aaa":dic2,
@"bbb":dic,
@"ar1":array
};
NSLog(@"dic3 %@",dic3);
//4.获得字典的长度
NSLog(@"count %ld",dic3.count);
//5.从字典中取值
NSString * str = [dic3 objectForKey:@"one"];
NSLog(@"str %@",str);
NSDictionary * dicTmp = [dic3 objectForKey:@"aaa"];
NSLog(@"dicTmp %@",dicTmp);
NSArray * arrayTmp = [dic3 objectForKey:@"ar1"];
NSLog(@"arrayTmp %@",arrayTmp);
//6.遍历
//取出所有的key值
NSArray * allkeys = [dic3 allKeys];
NSLog(@"allkeys %@",allkeys);
for (int i = 0; i < allkeys.count; i++)
{
NSString * key = [allkeys objectAtIndex:i];
//如果你的字典中存储的多种不同的类型,那么最好用id类型去接受它
id obj = [dic3 objectForKey:key];
NSLog(@"obj %@",obj);
}
//2.枚举器
NSEnumerator * enumerator = [dic3 objectEnumerator];
id value;
while (value = [enumerator nextObject]) {
NSLog(@"value %@",value);
}
}
return 0;
}

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