在关闭程序之前添加文件后如何从 file.txt 中检索信息

Posted 2023-03-06

【中文标题】在关闭程序之前添加文件后如何从 file.txt 中检索信息

【英文标题】：How can I retrieve information from a file.txt after adding it before turning off the program

【发布时间】：2020-07-10 16:48:56

【问题描述】：

我正在学习生成 .txt 文件以及如何编写和读取它们，我现在遇到的问题是我想制作一个程序，我可以在其中创建、编辑和删除看起来类似于表格的字符和这些新字符保存在file.txt中

看到角色有共同的属性，我考虑使用类，我不是这方面的专家，但我知道一点，我的主要想法是要求属性并生成一个对象并添加它到一个字符列表，这样做一切都很好，但是当你再次启动程序时数据不会保存

class PLAYER:
    def __init__(self,Name,Attack,Defense,Health):
        self.Name=Name
        self.Attack=Attack
        self.Defense=Defense
        self.Health=Health

options=[0,1,2,3]
characters=[]

while True:
    counter=0
    archive = open("players.txt","w")
    print("ID|NAME|ATTACK|DEFENSE|HEALTH")
    while counter != len(characters):
        print("(",counter,")", characters[0+counter].Name,characters[0+counter].Attack,characters[0+counter].Defense,characters[0+counter].Health)
        counter += 1
    print("Character Manager")
    print("( 0 ) Create")
    print("( 1 ) Edit")
    print("( 2 ) Delete")
    print("( 3 ) Exit")
    while True:#Choose the option
        try:
            option=int(input("-> "))
            while option not in options:
                print("Are you looking to find more options? Sorry, friend, there is no budget for that")
                option=int(input("-> "))
            break
        except ValueError:
            print("Please write the number in parentheses of the option you want to do")
        
    if option==3:#Exit
        archive.close()
        break
    elif option==0:#Crear
        NAME=input("What will his name be? ")
        while True:#Ataque
            try:
                ATTACK=int(input("How much attack will it have? "))
                break
            except:
                print("please put an integer value")
        while True:#Defensa
            try:
                DEFENSE=input("How much will your defense be? ")
                break
            except:
                print("please put an integer value")
        while True:#Vida
            try:
                HEALTH=input("How much life will it have?")
                break
            except:
                print("please put an integer value")
        characters.append(PLAYER(NAME,ATTACK,DEFENSE,HEALTH))
    elif option==1:#Edit
        print("Which character do you want to edit?")
        ID=int(input("-> "))
        characters.remove(characters[ID])
        NAME=input("What will be his new name? ")
        while True:#Ataque
            try:
                ATTACK=int(input("How much attack will it have? "))
                break
            except:
                print("please put an integer value")
        while True:#Defensa
            try:
                DEFENSE=input("How much will your defense be?")
                break
            except:
                print("please put an integer value")
        while True:#Vida
            try:
                HEALTH=input("How much life will it have?")
                break
            except:
                print("please put an integer value") 
        characters.append(PLAYER(NAME,ATTACK,DEFENSE,HEALTH))
    elif option==2:#Delete
        print("¿Qué personaje quieres eliminar?")
        ID=int(input("-> "))
        characters.remove(characters[ID])

到目前为止我还没有使用.txt文件，为了不再显示完整的代码，我将只放改变的部分

    counter=0
    archive = open("players.txt","w")
    print("ID|NAME|ATTACK|DEFENSE|HEALTH")
    while counter != len(characters):
        a=("(",counter,")", characters[0+counter].Name,characters[0+counter].Attack,characters[0+counter].Defense,characters[0+counter].Health)
        archive.write(a)
        archive.write("\n")
        counter += 1
    archive.close()
    archive = open("personajes.txt","r")
    print(archive.read())
    print("Character Manager")
    print("( 0 ) Create")
    print("( 1 ) Edit")
    print("( 2 ) Delete")
    print("( 3 ) Exit")

我这里发现的问题是write参数必须是str，不是tuple而是放的时候

a = str ("all the stuff")

在我看来

TypeError: str() takes at most 3 arguments (7 given)

所以现在我没有找到解决方法的想法，我希望你能帮助我解决这个问题，因为我自己找不到解决方案

我正在寻找的一个例子是这样的

ID|NAME|ATTACK|DEFENSE|HEALTH
Character Manager
( 0 ) Create
( 1 ) Edit
( 2 ) Delete
( 3 ) Exit

-> 0

What will his name be? Joseph

How much attack will it have? 20

How much will your defense be? 10

How much life will it have?50
ID|NAME|ATTACK|DEFENSE|HEALTH
( 0 ) Joseph 20 10 50
Character Manager
( 0 ) Create
( 1 ) Edit
( 2 ) Delete
( 3 ) Exit

但我希望当我开始时，如果有旧的注册字符会出现

如果我使用 f 字符串

    counter=0
    archive = open("players.txt","w")
    print("ID|NAME|ATTACK|DEFENSE|HEALTH")
    while counter != len(characters):
        a=f"( counter ) characters[counter].Name characters[counter].Attack characters[counter].Defense characters[counter].Health"
        archive.write(a)
        archive.write("\n")
        counter += 1
    archive.close()
    archive = open("personajes.txt","r")
    print(archive.read())

新字符被打印，但在关闭程序并重新打开之前创建的字符消失时

【问题讨论】：

您能否展示一个示例输入和您正在寻找的输出

您可以让类覆盖 __str__ 和 __repr__。或者使用 f 字符串：a=f"( counter ),characters[counter].Name characters[counter].Attack characters[counter].Defense characters[counter].Health"

我刚刚编辑了问题以显示我正在寻找的输出类型

使用 f-string 打印新字符，但在关闭程序并重新打开它时没有字符出现

使用pickle 将对象存储（序列化）到磁盘并检索（反序列化）它们。

【参考方案1】：

使用列表推导将所有行创建为字符串，然后使用 join 将它们全部与 \n

info = '\n'.join([list comprehension here])
file.write(info)

【参考方案2】：

您可以使用pickle 将对象存储和检索到磁盘。这是基于您的代码的示例：

import pickle

class Player:
    def __init__(self, name, attack, defense, health):
        self.name = name
        self.attack = attack
        self.defense = defense
        self.health = health
        
    def __str__(self):
        return f"self.name self.attack self.defense self.health"

# Create 2 objects and save
def create_and_save():
    p1 = Player("name1", 1, 2, 3)
    p2 = Player("name2", 4, 5, 6)
    with open("players.bin", "wb") as f:
        pickle.dump(p1, f)
        pickle.dump(p2, f)

# Load the previously store object and print them
def load_data():
    with open("players.bin", "rb") as f:
        p1 = pickle.load(f)
        p2 = pickle.load(f)
    print(p1)
    print(p2)

choice = int(input("1. Save, 2. Load: "))
if choice == 1:
    create_and_save()
else:
    load_data()

运行程序两次。第一次输入“1”，第二次输入“2”。

^{附注我已经修改了类成员名称以适应 pep guide。}