在lucene .net中查找字段的所有可用值

问题描述

如果我有一个字段x，可以包含y或z等值，是否有一种查询方法，以便我只能返回已索引的值?

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

Examplex 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

执行必需的查询将返回以下列表:test1，test2，test4

Performing required query would return a list of:test1, test2, test4

推荐答案

我之前已将其实现为扩展方法:

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());
    }
}

您可以像这样很容易地使用它:

You can use it very easily like this:

var allPossibleTermsForField = reader.UniqueTermsFromField("FieldName");

那将返回您想要的东西.

That will return you what you want.

由于有些心不在I，所以我跳过了上面的第一项.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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