MongoDB计算集合中子字符串的出现次数-MongoDBcountoccurancesofasubstringinacollection

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There is no any built-in operator to solve your request.

没有任何内置运算符可以解决您的请求。

You can try this query, but it has very poor performance:

您可以尝试此查询，但性能非常差：

db.chat.find().forEach(function(doc){
    print(doc["user"] + " > " + ((doc["message"].match(/foobar/g) || []).length))
})

If you could change your message field to array, then we could apply aggregation...

如果您可以将消息字段更改为数组，那么我们可以应用聚合...

EDIT:

编辑：

If you add array of splitted words into your entry, we can apply aggregation

如果在条目中添加分割单词数组，我们可以应用聚合

Sample:

样品：

{
    "_id" : ObjectId("569bb7040586bcb40f7d2539"),
    "user" : "username",
    "fullmessage" : "foobar foobar potato idontknow",
    "message" : [ 
        "foobar", 
        "foobar", 
        "potato", 
        "idontknow"
    ],
    "time" : NumberLong(1451775601469)
}

Aggregation. We create new entry for each array element, match given word (foobar, in this case) and then count matched result.

聚合。我们为每个数组元素创建新条目，匹配给定的单词（在这种情况下为foobar），然后计算匹配的结果。

db.chat.aggregate([
    {"$unwind" : "$message"},
    {"$match" : {"message" : {"$regex" : "foobar", "$options" : "i"}}},
    {"$group" : {_id:{"_id" : "$_id", "user" : "$user", "time" : "$time", "fullmessage" : "$fullmessage"}, "count" : {$sum:1}}},
    {"$project" : {_id:"$_id._id", "user" : "$_id.user", "time" : "$_id.time", "fullmessage" : "$_id.fullmessage", "count" : "$count"}}
])

Result:

结果：

[ 
    {
        "_id" : ObjectId("569bb7040586bcb40f7d2539"),
        "count" : 2,
        "user" : "username",
        "time" : NumberLong(1451775601469),
        "fullmessage" : "foobar foobar potato idontknow"
    }
]