Mongo通过正则表达式查找:仅返回匹配的字符串 [英] Mongo find by regex: return only matching string

问题描述

我的应用程序具有以下堆栈:

My application has the following stack:

在Ruby上的Sinatra-> MongoMapper-> MongoDB

Sinatra on Ruby -> MongoMapper -> MongoDB

应用程序将几个条目放入数据库中.为了交叉链接到其他页面，我添加了某种语法.例如:

The application puts several entries in the database. In order to crosslink to other pages, I've added some sort of syntax. e.g.:

咖啡是一种黑色的含咖啡因的液体，由豆类制成. {茶}是用树叶制成的.两种饮料有时都可以与{milk}一起享用

Coffee is a black, caffeinated liquid made from beans. {Tea} is made from leaves. Both drinks are sometimes enjoyed with {milk}

在此示例中，{Tea}将链接到另一个有关tea的数据库条目.

In this example {Tea} will link to another DB entry about tea.

我试图查询我的mongoDB有关所有链接术语"的信息.通常在红宝石中，我会做这样的事情:/{([a-zA-Z0-9])+}/其中，()将返回匹配的字符串.但是在mongo中，我得到了整个记录.

I'm trying to query my mongoDB about all 'linked terms'. Usually in ruby I would do something like this: /{([a-zA-Z0-9])+}/ where the () will return a matched string. In mongo however I get the whole record.

我如何才能得到mongo仅将我要查找的记录中匹配的部分退还给我.因此，对于上面的示例，它将返回:

How can I get mongo to return me only the matched parts of the record I'm looking for. So for the example above it would return:

["Tea", "milk"]

我试图避免将整个记录拉入Ruby并在那里进行处理

I'm trying to avoid pulling the entire record into Ruby and processing them there

推荐答案

我不知道我是否理解.

db.yourColl.aggregate([
{
    $match:{"yourKey":{$regex:'[a-zA-Z0-9]', "$options" : "i"}}
},
{
    $group:{
        _id:null,
        tot:{$push:"$yourKey"}
    }
}])

如果您不想在tot中重复，请使用$addToSet

If you don't want to have duplicate in totuse $addToSet

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