java 获取 LinkedHashMap 中的下一项？
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Get next item in LinkedHashMap?
提问by
I have the first key/value pair in a LinkedHashMap, which I get from a loop:
我在 LinkedHashMap 中有第一个键/值对，我从循环中得到：
for (Entry<String, String> entry : map.entrySet()) {
String key = entry.getKey();
String value = entry.getValue();
//put key value to use
break;
}
Later on, based on an event, I need the next key/value pair in the linkedHashMap. What is the best way to do this?
稍后，根据事件，我需要linkedHashMap 中的下一个键/值对。做这个的最好方式是什么？
采纳答案by gpeche
Get an iterator and use hasNext()and next():
获取迭代器并使用hasNext()and next()：
...
Iterator<Entry<String, String>> it = map.entrySet().iterator();
if (it.hasNext()) {
Entry<String, String> first = it.next();
...
}
...
if (eventHappened && it.hasNext()) {
Entry<String, String> second = it.next();
...
}
...
回答by Peter Lawrey
Its much easier to have the previous value if you need to compare to consecutive values.
如果您需要与连续值进行比较，那么获得前一个值要容易得多。
String pkey = null;
String pvalue = null;
for (Entry<String, String> entry : map.entrySet()) {
String key = entry.getKey();
String value = entry.getValue();
// do something with pkey/key and pvalue/value.
pkey = key;
pvalue = value;
}
回答by orangepips
Rather than for each loop, use an iterator.
而不是每个循环，使用迭代器。
Iterator it = map.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry)it.next();
String key = entry.getKey();
String value = entry.getValue();
// do something
// an event occurred
if (it.hasNext()) entry = (Map.Entry)it.next();
}
