java 从 HashMap 中提取值
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extracting values from HashMap
提问by Anurag Ramdasan
I was trying to learn and make understanding out of the working of a HashMap. So i created this hashmap to store certain values which upon displaying using an Iterator gives me outputs as
我试图从 HashMap 的工作中学习和理解。所以我创建了这个哈希图来存储某些值，这些值在使用迭代器显示时给我输出
1=2
2=3
3=4
and so on. This output i obtain using the Iterator.next()function. Now what my actual doubt is that since the type of this value returned in of an Iterator Object, if i need to extract only the right hand side values of the above equalities, is there any function for that? Something like a substring. Is there any way i could just get results as
等等。我使用该Iterator.next()函数获得的这个输出。现在我真正的疑问是，由于这个值的类型是在迭代器对象中返回的，如果我只需要提取上述等式的右侧值，是否有任何函数？类似子串的东西。有什么办法可以让我得到结果
2
3
4
Any help will be appreciated. thanks in advance.
任何帮助将不胜感激。提前致谢。
回答by Peter Lawrey
I would use something like
我会使用类似的东西
Map<Integer, Integer> map = new HashMap<>();
for(int value: map.values())
System.out.println(value);
回答by ControlAltDel
You are looking for map.values().
您正在寻找map.values().
回答by user949300
Map has a method called values() to get a Collection of all the values. (the right side)
Map 有一个叫做 values() 的方法来获取所有值的集合。（右侧）
Likewise, there is a method call keySet() to get a Set of all the keys. (the left side)
同样，有一个方法调用 keySet() 来获取所有键的 Set。(左侧)
回答by Jonathan Payne
import java.util.HashMap;
public class Test
{
public static void main( String args[] )
{
HashMap < Integer , Integer > map = new HashMap < Integer , Integer >();
map.put( 1 , 2 );
map.put( 2 , 3 );
map.put( 3 , 4 );
for ( Integer key : map.keySet() )
{
System.out.println( map.get( key ) );
}
}
}
回答by darrengorman
You need the Map#values()method which returns a Collection.
您需要Map#values()方法返回一个Collection.
You can then get an Iteratorfrom this collection in the normal way.
然后，您可以Iterator以正常方式从该集合中获取。
