python - 选择哪种文件模式并循环创建列表

Question

再次遇到另一个问题。我正在尝试制作一个“表格制作者” - 现在只是用字典创建文件并检查键。

我有两个问题:首先，我不知道是否有一种文件格式可以以二进制形式写入，但如果以前的文件已经存在，则不会覆盖它？我尝试了 (try, except) 方法，但异常(exception)的 FileExistsError 从未出现:/(在 createTable 函数中)

其次，我在创建列表时遇到问题。我创建了一个循环，要求将条目和值存储在单独的列表中。这些列表稍后将被压缩到字典中并腌制到文件中。 (在createTable函数中)

当然，如果还有其他错误，我希望他们指出:)

import pickle

def checkTable(nameOfTable) :

    try :
        #seeing what is it they are looking for
        prompt = input("What do you want to check?\n")
        with open("%s.pkl" % nameOfTable, "rb") as f:
            data = pickle.load(f)
            #getting what they want from the data from table
            whatTheyWant = data.get(prompt, "There is nothing like that in the table.\n")
            print(whatTheyWant)
    #if table doesn't exist
    except IOError as e:
        print("Sorry such a directory doesn't exist.\n")


def createTable(nameOfYourTable) :
    try :
        #opens a new file with the table
        with open("%s.pkl" %nameOfYourTable, "wb+") as f :
            decision = "yes"
            if decision == "yes" :
                #asking for entries and keys to put into the table
                #creates lists with entries and values to be zipped together
                entry.append = input("What is the entry?\n")
                value.append = input("What is the value of the entry?\n")
                decision = input("Do you want to go on? (yes/no)\n")
                i += 1
            else :
            #getting it all into a dictionary and putting it into a file
                table={dict(zip(entry, value))}
                pickle.dump(table, f)
    #if a file with the name already exists
    except FileExistsError as e :
        print("Sorry, a file with this name already exists.")


#what the person wants to do
answer = input("Hello. Do you want to create a table or check an existing one?\n")

#asking for the name of the new table
if answer == "create" :
    nameOfYourTable = input("What do you want the table to be called?\n")
    createTable(nameOfYourTable)
#asking what table to look in
elif answer == "check" :
    nameOfTable = input("What is the name of the table?\n")
    checkTable(nameOfTable)
else :
    print("\nThat's not a valid option.\n")

print("Thank you for using me. It was very nice.")

Answer 1

有一个文件模式正是您想要的，open(file, "x")，根据需要添加b或t您的需要。

在x模式下，仅当文件不已存在时才会创建，否则引发异常。 createTable 函数对我来说并没有真正的意义。 决策="is"然后如果决策=="is":？ 决策应该是一个全局？非常模糊。