如何迭代嵌套映射和多集？- Java/Guava
如何迭代嵌套映射和多集？- Java/Guava
提问于 2011-12-15 15:13:36
我应该如何使用这样的声明迭代嵌套Map？
Map<String, Multiset<String>>
请建议是否还有其他更有效地执行散列填充任务的hashmap/list？
import com.google.common.collect.Multiset;
import com.google.common.collect.TreeMultiset;
String[] foobarness = {"foo" , "bar", "ness", "foo",
"bar", "foo", "ness", "bar", "foo", "ness", "foo",
"bar", "foo", "ness", "bar", "ness", "foo", "bar",
"foo", "ness"};
String[] types = {"type::1", "type::2", "type::3",
"type::4",};
Map<String, Multiset<String>> typeTextCount =
new HashMap<String, Multiset<String>>();
Multiset<String> textAndCount
= TreeMultiset.create();
for (int i=0; i<types.length; i++) {
// I know it's kinda weird but in my task,
// i want to keep adding only 1 to the count for each entry.
// Please suggest if there is a better hashmap/list for such task.
if ((types[i]== "type::1") or (types[i]== "type::3")) {
for (String text : foobarness) {
// I don't worry too much about how i
// populate the Map, it is iterating through
// the Map that I have problem with.
textAndCount.put(text, 1);
}
}
if ((types[i]== "type::2") or (types[i]== "type::4")) {
for (String text : foobarness)
textAndCount.put(text, 1);
}
}那么现在hashmap已经被填充了，我如何迭代这个复杂的嵌套映射呢？我已经尝试了下面的代码，但是我只从我的Multiset获得了第一个getValue()：
Iterator<Entry<String, Multiset<String>>> itTTC =
typeTextCount.entrySet().iterator();
while (itTTC.hasNext()) {
Map.Entry textCt = (Map.Entry)itTTC.next();
System.out.println(textCt.getKey() + " :\t" + textCt.getValue());
itTTC.remove();
}Stack Overflow用户
回答已采纳
发布于 2011-12-15 15:25:51
在代码中，您没有将Multiset添加到Map中。这就是为什么你没有看到任何输出。
在您的代码中，我这样做了：
typeTextCount.put(types[i], textAndCount);在循环内部，然后使用相同的迭代器，我可以看到所有的输出如下：
type::3 : [bar x 24, foo x 32, ness x 24]
type::2 : [bar x 24, foo x 32, ness x 24]
type::4 : [bar x 24, foo x 32, ness x 24]
type::1 : [bar x 24, foo x 32, ness x 24]编辑:供参考的完整代码：
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import com.google.common.collect.Multiset;
import com.google.common.collect.TreeMultiset;
public class TestIterator {
private static String[] foobarness =
{
"foo", "bar", "ness", "foo", "bar", "foo", "ness", "bar", "foo", "ness", "foo", "bar", "foo", "ness",
"bar", "ness", "foo", "bar", "foo", "ness"
};
private static String[] types =
{
"type::1", "type::2", "type::3", "type::4",
};
public static void main(String[] args) {
Map<String, Multiset<String>> typeTextCount = new HashMap<String, Multiset<String>>();
Multiset<String> textAndCount = TreeMultiset.create();
for (int i = 0; i < types.length; i++) {
// I know it's kinda weird but in my task,
// I want to keep adding only 1 to the count for each entry.
// Please suggest if there is a better hashmap/list for such task.
if (("type::1".equals(types[i])) || ("type::3".equals(types[i]))) {
for (String text : foobarness) {
// I don't worry too much about how i
// populate the Map, it is iterating through
// the Map that I have problem with.
textAndCount.add(text, 1);
}
}
if (("type::2".equals(types[i])) || ("type::4".equals(types[i]))) {
for (String text : foobarness)
textAndCount.add(text, 1);
}
typeTextCount.put(types[i], textAndCount);
}
Iterator<Entry<String, Multiset<String>>> itTTC = typeTextCount.entrySet().iterator();
while (itTTC.hasNext()) {
Map.Entry textCt = (Map.Entry) itTTC.next();
System.out.println(textCt.getKey() + " :\t" + textCt.getValue());
itTTC.remove();
}
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/8522268
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