我需要帮助在我的词典程序

Question

def createdictionary(): 
    mydictionary = dict() 
    mydictionary['Computer']='Computer is an electronic machine.' 
    mydictionary['RAM']='Random Access Memory' 
    return mydictionary 

def insert(dictionary): 
    print("Enter the keyword you want to insert in the dictionary: ") 
    key=input() 
    print("Enter its meaning") 
    meaning=input() 
    dictionary[key]=meaning 
    f = open('dict_bckup.txt','a') 
    f.write(key) 
    f.write('=') 
    f.write(meaning) 
    f.write(';\n') 
    f.close() 
    print("Do you want to insert again? y/n") 
    ans=input() 
    if (ans == 'y' or ans=='Y'): 
     insert(dictionary) 

def display(dictionary): 
    print("The contents of the dictionary are : ") 
    f = open('dict_bckup.txt','r') 
    print(f.read()) 
    f.close() 

def update(dictionary): 
    print("Enter the word whose meaning you want to update") 
    key=input() 
    #i want to edit the meaning of the key in the text file 
    f = open('dict_bckup.txt','w') 
    if key in dictionary: 
     print(dictionary[key]) 
     print("Enter its new meaning: ") 
     new=input() 
     dictionary[key]=new 
    else: 
     print("Word not found! ") 
    print("Do you want to update again? y/n") 
    ans=input() 
    if (ans=='y' or ans=='Y'): 
     update(dictionary) 

def search(dictionary): 
    print("Enter the word you want to search: ") 
    word=input() 
    if word in dictionary: 
     print(dictionary[word]) 

else: 
    print("Word not found! ") 
print("Do you want to search again? y/n") 
ans=input() 
if(ans=='y' or ans=='Y'): 
    search(dictionary) 


def delete(dictionary): 
    print("Enter the word you want to delete: ") 
    word=input() 
    if word in dictionary: 
     del dictionary[word] 
     print(dictionary) 
    else: 
     print("Word not found!") 

    print("Do you want to delete again? y/n ") 
    ans=input() 
    if (ans == 'y' or ans == 'Y'): 
     delete(dictionary) 

def sort(dictionary): 
    for key in sorted(dictionary): 
     print(" %s: %s "%(key,(dictionary[key]))) 


def main(): 
    dictionary=createdictionary() 
    while True: 

     print("""    Menu 
      1)Insert 
      2)Delete 
      3)Display Whole Dictionary 
      4)Search 
      5)Update Meaning 
      6)Sort 
      7)Exit 
      Enter the number to select the coressponding field """) 

     ch=int(input()) 

     if(ch==1): 
      insert(dictionary) 

     if(ch==2): 
      delete(dictionary) 

     if(ch==3): 
      display(dictionary) 

     if(ch==4): 
      search(dictionary) 

     if(ch==5): 
      update(dictionary) 

     if(ch==6): 
      sort(dictionary) 

     if(ch==7):           
      break 


main() 

我是新来的蟒蛇。我一直在努力几天才能得到这个。但仍然没有找到解决办法。事情最初我做了一个简单的字典程序，它存储了单词和它们的含义。然后我想我应该永久保存这些词。我有些尝试将文字存储在文本文件中并显示它。但我没有得到如何搜索文本文件中的单词。假设我找到了这个词，我想更新它的意思。所以我应该怎么做。因为如果我使用'w'来重写它的整个文本文件，它会被重写。而且我应该如何删除它。我知道我在文件中插入单词的方式也是错误的。请帮我解决一下这个。

Answer 1

你说得对，将这些值存储在一个简单的文本文件中是一个坏主意。如果你想更新一个单词，你必须重写整个文件。而搜索单个单词时，最终可能会搜索文件中的每个单词。

有一些专门为字典设计的数据结构（例如Trie树），但假设你的字典并不真的很大，你可以使用一个sqlite数据库。 Python有sqlite3库。查看documentation了解更多信息。

Answer 2

正如@Vaibhav Desai所说，您可以定期编写整本字典。例如考虑在picklemodule其写入序列化对象：

import pickle 

class MyDict(object): 
    def __init__(self, f, **kwargs): 
     self.f = f 
     try: 
      # Try to read saved dictionary 
      with open(self.f, 'rb') as p: 
       self.d = pickle.load(p) 
     except: 
      # Failure: recreating 
      self.d = {} 
     self.update(kwargs) 

    def _writeback(self): 
     "Write the entire dictionary to the disk" 
     with open(self.f, 'wb') as p: 
      pickle.dump(p, self.d) 

    def update(self, d): 
     self.d.update(d) 
     self._writeback() 

    def __setitem__(self, key, value): 
     self.d[key] = value 
     self._writeback() 

    def __delitem__(self, key): 
     del self.d[key] 
     self._writeback() 

    ... 

这将改写整个字典到磁盘每次进行修改，这可能是有意义的某些情况下的时间，但可能不是最有效的。您也可以制定一个更为巧妙的机制，定期调用_writeback，或要求明确调用_writeback。

正如其他人所建议的，如果你需要大量写入字典，你会使用sqlite3module，有一个SQL表作为你的字典会更好：

import sqlite3 

class MyDict(object): 
    def __init__(self, f, **kwargs): 
     self.f = f 
     try: 
      with sqlite3.connect(self.f) as conn: 
       conn.execute("CREATE TABLE dict (key text, value text)") 
     except: 
      # Table already exists 
      pass 

    def __setitem__(self, key, value): 
     with sqlite3.connect(self.f) as conn: 
      conn.execute('INSERT INTO dict VALUES (?, ?)', str(key), str(value)) 

    def __delitem__(self, key): 
     with sqlite3.connect(self.f) as conn: 
      conn.execute('DELETE FROM dict WHERE key=?', str(key)) 

    def __getitem__(self, key): 
     with sqlite3.connect(self.f) as conn: 
      key, value = conn.execute('SELECT key, value FROM dict WHERE key=?', str(key)) 
      return value 

    ... 

这只是一个例如，你可以维持连接打开，并要求它明确关闭，或排队查询......但它应该给你一个粗略的想法，你可以如何将数据保存到磁盘。

通常，Python文档的Data Persistence部分可以帮助您找到最适合您问题的模块。

Answer 3

首先，每次更新或插入字典时写入磁盘是一个非常糟糕的主意 - 您的程序只是用尽了太多的I/O。因此，更简单的方法是将键值对存储在字典中，并在程序退出时或以某个固定的时间间隔将其保存到磁盘中。另外，如果你不喜欢以人类可读形式（例如纯文本文件）将数据存储在磁盘上，您可以考虑使用如here所示的内置泡菜模块将数据保存到定义良好的磁盘位置。因此，在程序启动时，您可以从这个明确定义的位置读取数据，并将数据“清理”回到字典对象中。这样您就可以单独使用字典对象，甚至可以轻松完成查找项目或删除项目等操作。请参阅下面的脚本来解决您的需求。我已经使用pickle模块来保存该文件，您可能希望将其转储到文本文件并作为单独的练习读取它。另外，我还没有介绍我的功能，例如后缀为，例如，insert2，以便您可以将您的功能与我的功能进行比较并了解其差异：

另一件事 - 您的程序中存在错误;你应该使用的raw_input（）如果字典不是太大读取用户输入和不输入（）

import pickle 
import os 

def createdictionary(): 
    mydictionary = dict() 
    mydictionary['Computer']='Computer is an electronic machine.' 
    mydictionary['RAM']='Random Access Memory' 
    return mydictionary 

#create a dictionary from a dump file if one exists. Else create a new one in memory.  
def createdictionary2(): 

    if os.path.exists('dict.p'): 
     mydictionary = pickle.load(open('dict.p', 'rb')) 
     return mydictionary 

    mydictionary = dict() 
    mydictionary['Computer']='Computer is an electronic machine.' 
    mydictionary['RAM']='Random Access Memory' 
    return mydictionary 

def insert(dictionary): 
    print("Enter the keyword you want to insert in the dictionary: ") 
    key=raw_input() 
    print("Enter its meaning") 
    meaning=raw_input() 
    dictionary[key]=meaning 
    f = open('dict_bckup.txt','a') 
    f.write(key) 
    f.write('=') 
    f.write(meaning) 
    f.write(';\n') 
    f.close() 
    print("Do you want to insert again? y/n") 
    ans=raw_input() 
    if (ans == 'y' or ans=='Y'): 
     insert(dictionary) 

#custom method that simply updates the in-memory dictionary 
def insert2(dictionary): 
    print("Enter the keyword you want to insert in the dictionary: ") 
    key=raw_input() 
    print("Enter its meaning") 
    meaning=raw_input() 
    dictionary[key]=meaning 

    print("Do you want to insert again? y/n") 
    ans=raw_input() 
    if (ans == 'y' or ans=='Y'): 
     insert(dictionary) 



def display(dictionary): 
    print("The contents of the dictionary are : ") 
    f = open('dict_bckup.txt','r') 
    print(f.read()) 
    f.close() 

#custom display function - display the in-mmeory dictionary 
def display2(dictionary): 
    print("The contents of the dictionary are : ") 
    for key in dictionary.keys(): 
     print key + '=' + dictionary[key] 

def update(dictionary): 
    print("Enter the word whose meaning you want to update") 
    key=input() 
    #i want to edit the meaning of the key in the text file 
    f = open('dict_bckup.txt','w') 
    if key in dictionary: 
     print(dictionary[key]) 
     print("Enter its new meaning: ") 
     new=raw_input() 
     dictionary[key]=new 
    else: 
     print("Word not found! ") 
    print("Do you want to update again? y/n") 
    ans=input() 
    if (ans=='y' or ans=='Y'): 
     update(dictionary) 

#custom method that performs update of an in-memory dictionary   
def update2(dictionary): 
    print("Enter the word whose meaning you want to update") 
    key=input() 
    #i want to edit the meaning of the key in the text file 

    if key in dictionary: 
     print(dictionary[key]) 
     print("Enter its new meaning: ") 
     new=raw_input() 
     dictionary[key]=new 
    else: 
     print("Word not found! ") 
    print("Do you want to update again? y/n") 
    ans=raw_input() 
    if (ans=='y' or ans=='Y'): 
     update(dictionary) 

def search(dictionary): 
    print("Enter the word you want to search: ") 
    word=raw_input() 
    if word in dictionary: 
     print(dictionary[word]) 

    else: 
     print("Word not found! ") 
    print("Do you want to search again? y/n") 
    ans=raw_input() 
    if(ans=='y' or ans=='Y'): 
     search(dictionary) 


def delete(dictionary): 
    print("Enter the word you want to delete: ") 
    word=raw_input() 
    if word in dictionary: 
     del dictionary[word] 
     print(dictionary) 
    else: 
     print("Word not found!") 

    print("Do you want to delete again? y/n ") 
    ans=raw_input() 
    if (ans == 'y' or ans == 'Y'): 
     delete(dictionary) 

def sort(dictionary): 
    for key in sorted(dictionary): 
     print(" %s: %s "%(key,(dictionary[key]))) 

#this method will save the contents of the in-memory dictionary to a pickle file 
#of course in case the data has to be saved to a simple text file, then we can do so too 
def save(dictionary): 
    #open the dictionary in 'w' mode, truncate if it already exists 
    f = open('dict.p', 'wb') 
    pickle.dump(dictionary, f) 




def main(): 
    dictionary=createdictionary2() #call createdictionary2 instead of creatediction 
    while True: 

     print("""    Menu 
      1)Insert 
      2)Delete 
      3)Display Whole Dictionary 
      4)Search 
      5)Update Meaning 
      6)Sort 
      7)Exit 
      Enter the number to select the coressponding field """) 

     ch=int(input()) 

     if(ch==1): 
      insert2(dictionary) #call insert2 instead of insert 

     if(ch==2): 
      delete(dictionary) 

     if(ch==3): 
      display2(dictionary) #call display2 instead of display 

     if(ch==4): 
      search(dictionary) 

     if(ch==5): 
      update2(dictionary) #call update2 instead of update 

     if(ch==6): 
      sort(dictionary) 

     if(ch==7):           
      #save the dictionary before exit 
      save(dictionary); 
      break 


main()