我应该如何使用这样的声明迭代嵌套映射?
-
Map<String, Multiset<String>>
请建议是否有其他 HashMap /列表可以更有效地完成此哈希填充任务?
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);
}
}
现在 HashMap 已填充,我如何迭代该复杂的嵌套映射? 我已经尝试了下面的代码,但我只从我的 Multiset 中获得了第一个 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();
}
最佳答案
在您的代码中,您没有将 Multiset
添加到 Map
中。这就是为什么您看不到任何输出。
在你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,我可以看到像这样的所有输出:
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:完整代码供引用:
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();
}
}
}
关于java - 如何迭代Nested Map和Multiset? - java / Guava ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/8522268/