无法指定DB [Collection]的条件。

发布于 2025-01-20 05:59:42 字数 1615 浏览 4 评论 0原文

一直试图自己解决这个问题，所以我们有以下声明：

练习 5.1（代码）使用 MongoDB 集合中存储的数据和评论进行计数
进行评论的不同用户的数量（即计算reviewerID字段的不同值的数量）
给出至少一个差评（小于或等于 2 星）的不同用户的数量
收到评论的不同书籍的数量（即计算字段asin的不同值的数量）。

这是我的代码：

n_users = len(db[reviews_collection].distinct("reviewerID"))
n_users_bad_rating = len(db[reviews_collection].distinct("reviewerID", {"overall": {"$lte": 2.0}}))
n_books = len(db[reviews_collection].distinct("asin"))

print(f"There are {n_users} distinct users.")
print(f"There are {n_users_bad_rating} distinct users who gave at least one bad rating (less or equal to 2 stars).")
print(f"There are {n_books} distinct books in the reviews.")

这是我得到的输出：

有 3613 个不同的用户。有 0 个不同的用户给出了至少 1 个差评（小于或等于 2 星）。评论中有 3807 种不同的书籍。

集合中的数据示例：

{'_id': ObjectId('6252c21c2ee307d4d522af0a'),
 'appreciation': 'liked',
 'asin': 'B000R93D4Y',
 'book_index': 0,
 'helpful': [3, 3],
 'overall': 5.0,
 'reviewText': 'A strange world full of strange creatures, knights, and '
               'beautiful maidens.  The magical aspect of healing was a nice '
               'touch.',
 'reviewTime': '06 23, 2013',
 'reviewerID': 'A195CNOUUIT4SU',
 'summary': 'Great tale of dragons',
 'train_val_test': 'train',
 'unixReviewTime': 1371945600,
 'user_index': 0}

问题：为什么我无法使用条件？我在笔记本中还有其他练习，其中要求我查询数据库，除非我尝试指定条件，否则它工作得很好。当我使用循环时，它告诉我有一个“TypeError：字符串索引必须是 int”

原文

Have been trying to solve it by myself so we have the following statement:

Exercise 5.1 (code) Using the data stored in the MongoDB collection with the reviews, count
The number of distinct users who made a review (i.e. count the number of distinct values for the field reviewerID)
The number of distinct users who gave at least one bad rating (less or equal that 2 stars)
The number of distinct books which received a review (i.e. count the number of distinct values for field asin).

Here is my code:

n_users = len(db[reviews_collection].distinct("reviewerID"))
n_users_bad_rating = len(db[reviews_collection].distinct("reviewerID", {"overall": {"$lte": 2.0}}))
n_books = len(db[reviews_collection].distinct("asin"))

print(f"There are {n_users} distinct users.")
print(f"There are {n_users_bad_rating} distinct users who gave at least one bad rating (less or equal to 2 stars).")
print(f"There are {n_books} distinct books in the reviews.")

Here is the output I get:

There are 3613 distinct users.
There are 0 distinct users who gave at least one bad rating (less or equal to 2 stars).
There are 3807 distinct books in the reviews.

Example of what the data in the collection looks like:

{'_id': ObjectId('6252c21c2ee307d4d522af0a'),
 'appreciation': 'liked',
 'asin': 'B000R93D4Y',
 'book_index': 0,
 'helpful': [3, 3],
 'overall': 5.0,
 'reviewText': 'A strange world full of strange creatures, knights, and '
               'beautiful maidens.  The magical aspect of healing was a nice '
               'touch.',
 'reviewTime': '06 23, 2013',
 'reviewerID': 'A195CNOUUIT4SU',
 'summary': 'Great tale of dragons',
 'train_val_test': 'train',
 'unixReviewTime': 1371945600,
 'user_index': 0}

Question: Why am I unable to use conditions? I have other exercices in the notebook where am I asked to query the database it works perfectly fine except if I try to specify conditions. When I use a loop it tells me that I have a "TypeError: string indexes must be int"

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梦途 2025-01-27 05:59:42

以下是如何通过聚合框架查找总体 <=2 的 reviewerID 的不同值的一种方法：

db.collection.aggregate([
{
 $match: {
  "overall": {
    "$lte": 2.0
  }
 }
},
{
 "$group": {
  "_id": "TotalUnique",
  "unique": {
    "$addToSet": "$reviewerID"
  }
 }
}
])

playground

Here is one option how to find distinct values for reviewerID having overall <=2 via aggregation framework:

db.collection.aggregate([
{
 $match: {
  "overall": {
    "$lte": 2.0
  }
 }
},
{
 "$group": {
  "_id": "TotalUnique",
  "unique": {
    "$addToSet": "$reviewerID"
  }
 }
}
])

playground

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