在 lucene .net 中查找字段的所有可用值 [英] Find all available values for a field in lucene .net
问题描述
如果我有一个字段 x,它可以包含一个值 y 或 z 等,有没有一种方法可以查询,以便我可以只返回已被索引的值?
If I have a field x, that can contain a value of y, or z etc, is there a way I can query so that I can return only the values that have been indexed?
示例x 可用的可设置值 = test1, test2, test3, test4
Example x available settable values = test1, test2, test3, test4
第 1 项:字段 x = test1
Item 1 : Field x = test1
第 2 项:字段 x = test2
Item 2 : Field x = test2
第 3 项:字段 x = test4
Item 3 : Field x = test4
第 4 项:字段 x = test1
Item 4 : Field x = test1
执行所需的查询将返回以下列表:测试1,测试2,测试4
Performing required query would return a list of: test1, test2, test4
推荐答案
我之前已经实现了这个作为扩展方法:
I've implemented this before as an extension method:
public static class ReaderExtentions
{
public static IEnumerable<string> UniqueTermsFromField(
this IndexReader reader, string field)
{
var termEnum = reader.Terms(new Term(field));
do
{
var currentTerm = termEnum.Term();
if (currentTerm.Field() != field)
yield break;
yield return currentTerm.Text();
} while (termEnum.Next());
}
}
您可以像这样非常轻松地使用它:
You can use it very easily like this:
var allPossibleTermsForField = reader.UniqueTermsFromField("FieldName");
这会让你得到你想要的.
That will return you what you want.
由于心不在焉,我跳过了上面的第一个学期.我已经相应地更新了代码以使其正常工作.
I was skipping the first term above, due to some absent-mindedness. I've updated the code accordingly to work properly.
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