Python：如何更新嵌套字典中键值对的值？ [英] Python: How to update value of key value pair in nested dictionary?

问题描述

我想要创建一个反转的文档索引，因此我需要知道一个集合中的所有独特的单词，已使用此 answer按顺序二创建一个嵌套字典。提供的解决方案工作正常，但有一个问题。

首先，我打开文件，并制作一个唯一字的列表。这些独特的词我想要比较的原始文件。当有匹配时，频率计数器应该被更新并且它的值被存储在二维数组中。

输出应该最终看起来像这样：

  word1，{doc1：freq}，{doc2：freq}< br> 
 word2，{doc1：freq}，{doc2：freq}，{doc3：freq} 
等.... 
  

问题是我不能更新字典变量。当尝试这样做时，我得到的错误：

 文件scriptV3.py，第45行，在主
 freq = dictionary [keyword] [filename] + 1 
 TypeError：不支持的操作数类型为+：'AutoVivification'和'int'
  

我想我需要以某种方式将AutoVivification的实例转换为int ....

如何去？

提前感谢

我的代码：

 ＃！/ usr / bin / env python 
＃encoding：utf-8 
 
 import sys 
 import os 
 import re 
 import glob 
 import string 
 import sets 
 
 class AutoVivification（dict）：
实现perl的自动更新特性。 b $ b def __getitem __（self，item）：
 try：
 return dict .__ getitem __（self，item）
，除了KeyError：
 value = self [item] = type self）（）
返回值
 
 def main（）：
 pad ='temp /'
 dictionary = AutoVivification（）
 docID = 0 
用于glob.glob（os.path.join（pad，'* .html'））中的文件：＃对于指定文件夹中的所有文件：
 docID = docID + 1 
 filename = doc（doc）+ str（docID）
 text = open（files，'r'）read（）以字符串的形式返回文件内容
 text = extract（text，'< < / pre>'）#call提取函数以从< pre>标签
 text = text.lower（）＃所有小写字母
 exclude = set（string.punctuation）#sets所有标点符号的列表
 text =''.join如果字符不在排除）＃使用创建排除列表从文件中删除字符
 text = text.split（）#creates从字符串列表（数组）
 uniques = set（text）#make list 
 
对于uniques中的关键字：＃对于每个独特的单词do 
用于文本中的单词：＃对于doc中的每个单词：
 if（word ==关键字和字典[关键字] [文件名]不是无）：#if有关键字增量计数器发生
 freq = dictionary [关键字] [文件名]＃我们失败，实例为整数。 
 freq = dictionary [keyword] [filename] + 1 
 print（keyword，dictionary [keyword]）
 else：
 dictionary [word] [filename] b 
 #extract子字符串1和2之间的文本
 def extract（text，sub1，sub2）：
 return text.split（sub1,1）[ -  1] .split（sub2，1 ）[0] 
 
如果__name__ =='__main__'：
 main（）
  

<可以使用Python的collections.defaultdict而不是创建一个AutoVivification类，然后将字典实例化为该类型的对象。

  import collections 
 dictionary = collections.defaultdict（lambda：collections.defaultdict（int））
  

这将创建一个默认值为0的字典字典。当您希望增加一个条目时，使用：

  dictionary [keyword] [filename] + = 1 
  

i am trying to make an inversed document index, therefore i need to know from all unique words in a collection in which doc they occur and how often.

i have used this answer in order two create a nested dictionary. The provided solution works fine, with one problem though.

First i open the file and make a list of unique words. These unique words i than want to compare with the original file. When there is a match, the frequency counter should be updated and its value be stored in the two dimensional array.

output should eventually look like this:

word1, {doc1 : freq}, {doc2 : freq} <br>
word2, {doc1 : freq}, {doc2 : freq}, {doc3:freq}
etc....

Problem is that i cannot update the dictionary variable. When trying to do so i get the error:

  File "scriptV3.py", line 45, in main
    freq = dictionary[keyword][filename] + 1
TypeError: unsupported operand type(s) for +: 'AutoVivification' and 'int'

I think i need to cast in some way the instance of AutoVivification to int....

How to go?

thanks in advance

my code:

#!/usr/bin/env python 
# encoding: utf-8

import sys
import os
import re
import glob
import string
import sets

class AutoVivification(dict):
    """Implementation of perl's autovivification feature."""
    def __getitem__(self, item):
        try:
            return dict.__getitem__(self, item)
        except KeyError:
            value = self[item] = type(self)()
            return value

def main():
    pad = 'temp/'
    dictionary  = AutoVivification()
    docID = 0
    for files in glob.glob( os.path.join(pad, '*.html') ):  #for all files in specified folder:
        docID = docID + 1
        filename = "doc_"+str(docID)
        text = open(files, 'r').read()                      #returns content of file as string
        text = extract(text, '<pre>', '</pre>')             #call extract function to extract text from within <pre> tags
        text = text.lower()                                 #all words to lowercase
        exclude = set(string.punctuation)                   #sets list of all punctuation characters
        text = ''.join(char for char in text if char not in exclude) # use created exclude list to remove characters from files
        text = text.split()                                 #creates list (array) from string
        uniques = set(text)                                 #make list unique (is dat handig? we moeten nog tellen)

        for keyword in uniques:                             #For every unique word do   
            for word in text:                               #for every word in doc:
                if (word == keyword and dictionary[keyword][filename] is not None): #if there is an occurence of keyword increment counter 
                    freq = dictionary[keyword][filename]    #here we fail, cannot cast object instance to integer.
                    freq = dictionary[keyword][filename] + 1
                    print(keyword,dictionary[keyword])
                else:
                    dictionary[word][filename] = 1

#extract text between substring 1 and 2 
def extract(text, sub1, sub2): 
    return text.split(sub1, 1)[-1].split(sub2, 1)[0]    

if __name__ == '__main__':
    main()

解决方案

One could use Python's collections.defaultdict instead of creating an AutoVivification class and then instantiating dictionary as an object of that type.

import collections
dictionary = collections.defaultdict(lambda: collections.defaultdict(int))

This will create a dictionary of dictionaries with a default value of 0. When you wish to increment an entry, use:

dictionary[keyword][filename] += 1

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