ValueError：<太多解压值>

Question

任务是使用MongoDB查找，排序和删除学生'type'：“家庭作业”和最低分数。我也尝试使用toArray()函数，但它给出了一个错误。现在我尝试在文档中继续前进，并删除最低分数的最后一个排序文档。

import pymongo 
import sys  

#establish a connection to the database 
connection = pymongo.MongoClient("mongodb://localhost") 

def delete_lowest_doc(): 

    #get a handle to the students database 
    db=connection.students 
    grades = db.grades 


    try: 
     for i in range(0,grades.find().count()): 
      docs_1 = grades.find({'type':"homework", 'student_id':i}).sort(['score',-1]) 

      counter_1 = grades.find({'type':"homework",'student_id':i}) 
      counter_2 = counter_1.sort(['score',-1]).count() 

      while (counter_2>0): 
       doc = docs_1.next(); 
       counter_2=counter_2-1; 
      grades.remove(doc) 


    except Exception as e: 
     print ("Unexpected error:", type(e), e) 

delete_lowest_doc() 

Answer 1

collection.find只需要一个位置参数，并且您给了它两个。

改变你的呼叫，使它们看起来像下面这样：grades.find({"type": "homework", "student_id": i})。