Question

我无法在聚合中使用以下正则表达式。我读了很多例子，但它没有用。我想要的是排除具有3个或更少字符的单词（例如：1 a2 aaa a-）。然而，他们仍然出现。

这是我的正则表达式（我认为这是正确的）\b\w?\w?\w?\b。

这是聚合：

Meteor.publish("topics", function () {
  ReactiveAggregate(this, Articles, [
    {
      $project: {
              topic: { $split: ["$title", " "] },

              article: "$$ROOT"
      }
    },
    {
      $unwind: {
              path: "$topic"
      }
    },
    {
      $match: {
              topic: { $nin: ["sports", "\b\w?\w?\w?\b"] }
      }
    },
    {
      $group: {
              _id: "$topic",
              count: { $sum: 1 },
              articles: { $push: "$article" }
      }
    }
  ], { clientCollection: "clientTopic" });
});

示例：

    /* Article 1 */
{
    "_id" : "SB4mKAxaBijQXnS73",
    "title" : "Messi signs new contract with Barcelona"
}
/* Article 2 */
{
     "_id" : "rhqioBkePzGCrRFLp",
     "title" : "Messi has 30 years old"
 }
/* Article 3 */
{
      "_id" : "X6LochRZw32op39W8",
      "title" : "President of Argentina visits Messi"
}

我想得到一个像：

这样的集合

Messi ==> {_id: "Messi", articles: [Article 1, Article 2, Article 3], count: 3 }
signs ==> {_id: "signs", articles: [Article 1], count: 1 }
contract ==> {_id: "contract", articles: [Article 1], count: 1 }
with ==> {_id: "with", articles: [Article 1], count: 1 }
Barcelona  ==> {_id: "Barcelona", articles: [Article 1], count: 1 }

years  ==> {_id: "years", articles: [Article 2], count: 1 }

President  ==> {_id: "President", articles: [Article 3], count: 1 }
Argentina  ==> {_id: "Argentina", articles: [Article 3], count: 1 }
visits     ==> {_id: "visits", articles: [Article 3], count: 1 }

如您所见，单词new，has，30，old，of不应出现，因为它们的长度不超过3个字符

其标题中包含sports字样的文章不包含在集合中，但是与正则表达式匹配的文章包含。

Answer 1

数组中的每个元素在单词前面用^读取，例如[＆＃39; ^工作＆＃39;，＆＃39; ^ accus＆＃39;，＆＃39; ^ planet＆＃39;]

OR

var words = [/ hello /，/ ^ world /]; //正则表达式数组 db.getCollection（＆＃39; word collection＆＃39;）。find（{＆＃34; word＆＃34;：{$ in：words}}）;

Answer 2

如果要排除长度为3或小于3的单词，则可以使用/ \ w {4，} /

Meteor.publish("topics", function () {
  ReactiveAggregate(this, Articles, [
    {
      $project: {
              topic: { $split: ["$title", " "] },

              article: "$$ROOT"
      }
    },
    {
      $unwind: {
              path: "$topic"
      }
    },
    {
      $match: {
              topic: { $nin: ["sports", "\w{4,}"] }
      }
    },
    {
      $group: {
              _id: "$topic",
              count: { $sum: 1 },
              articles: { $push: "$article" }
      }
    }
  ], { clientCollection: "clientTopic" });
});

您可以将此链接用于测试正则表达式https://regex101.com/

$ nin mongo中的用户正则表达式

2 个答案: