Python：将电子邮件和姓名写入字典和文件

Question

I want to be able to write this without Pickling and I need to be able to save information from the Dict to the file and when I reload the program I can grab the info from the file. Currently the code I have writes onto the file and can take from the dict but I cannot grab the info from the actual file itself.

Problem:

Write a program that keeps names and email addresses in a dictionary as key-value pairs. The program should display a menu that lets the user look up a person's email address, add a new name and email address, change an existing email address, and delete an existing name and email address. The program should save the data stored a dictionary to a file when the user exits the program. Each time the program starts, it should retrieve the data from the file and store it in a dictionary.

The Code I have:

#dictionary to store records

dictionary=dict()
def add_record(name, email):
    dictionary[name]=email
    save()

#saving values to file
def save():   
    with open('emails.txt', 'w') as handle:
        handle.write(str(dictionary))
        handle.close()

#looks up email for given name
def lookup_email(name):
    read()
    if name in dictionary.keys():
        return dictionary[name]

#delets an email of given email
def delete_entry(name):
    read()
    if name in dictionary.keys():
        dictionary[name]=None
        del dictionary[name]
        save()
        return True
    return False
#Menu display
def menu():
    print("")
    print("Menu")
    print("-----------------------------------")
    print("1. Look up an email address")   
    print("2. Add a new name and email address")
    print("3. Change an existing email address")
    print("4. Delete a name and email address")
    print("5.Quit the program")
    print("")
    try:
        selection=int(input("Enter your choice: "))
        return selection
    except:
        print("Invalid Input")
#reads data from file
def read():
   with open("emails.txt", "r") as file:
    for line in file:
        key, value = line.strip().split(",")
        dictionary[key] = value
    
    
#Main function execution starts from here
if __name__ == '__main__':   
  
    while True:
        choice=menu()
        if choice==1:
            name=input("Enter a name: ")
            try:
                email=lookup_email(name)
                if(email!=None):
                    print(email)
                else:
                    print("No Data Found")
            except: 
                print("The specified name was not found")
        elif choice==2:
            name=input("Enter name: ")
            email=input("Enter Email Address: ")
            add_record(name, email)
            print("Name and Email has been added")
        elif choice==3:
            name=input("Enter the Name: ")
            email=input("Enter new Email Address")
            add_record(name, email)
            print("Information updated")
        elif choice==4:
            name=input("Enter the Name: ")
            try:
                delete_entry(name)
                print("Information deleted")
  
            except:
                print("Something went wrong!!! please try again later")
        elif choice==5:
            save()
            print("Information Saved")
            break;
        else:
            print("invalid input")

Answer 1

You should not save your file like that (by converting the dictionary to a string then outputting it to a file) and rather should turn to other safe and commonly used solutions. I'm not entirely sure why you would refuse to use pickle , but json is always another good substitute that works well with dictionaries.

from json import loads, dumps

# Saving
def save():   
    with open('emails.txt', 'w') as handle:
        handle.write(dumps(dictionary))
        handle.close()

# Loading
def load():   
    with open('emails.txt', 'w') as handle:
        dictionary = loads(handle.read())
        handle.close()