Pickle - 無法正確存儲附加字典到列表

Question

我正在嘗試將多個字典的列表保存在一個 pickle 文件中，並且能夠隨時在列表中存儲一個新的附加字典並將其保存在 pickle 文件中，然后將 pickle 文件作為字典列表加載。 到目前為止，代碼的行為如下：

我第一次嘗試在列表中附加字典時，pickle 文件如下所示（數據已成功保存）：

Running info()......

===================================================
Existing data: []
===================================================

Running save_score()......

Inside try: {}
============================================
Existing data: [{}]
New data: {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}
Saved Data: [{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}]
===================================================

我第二次嘗試在列表中附加字典時，pickle 文件如下所示：

Running info()......

===================================================
Existing data: [[{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}]]
===================================================

Running save_score()......

Inside try: [{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}]
============================================
Existing data: [[{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}], [{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}]]
New data: {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}
Saved Data: [[{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}], [{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}], {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}]
===================================================

正如您所看到的（字典中的值在上面的示例中不是問題），而不是附加到現有列表，每次都會在列表中創建一個新列表。 到目前為止，我還沒有設法解決這個問題並獲得預期的輸出。

預期的輸出應該是：

Saved Data: [{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}, {}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}]

相反，輸出是：

Saved Data: [[{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}], [{}, {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}], {'ComputerName': 'computer name', 'PlayerName': 'user 1', 'ComputerScore': 3, 'PlayerScore': 1}]

代碼如下：

import pickle

data = []
computer_name = "computer name"
username = "user 1"
computer_score = 3
human_score = 1

def save_score():
    try:
        existing_data = pickle.load(open("w6_project.p", "rb"))
        print("Inside try: {}".format(existing_data))
        data.append(existing_data)
    except (OSError, IOError) as e:
        pickle.dump({}, open("w6_project.p", "wb"))
    new_data = {"ComputerName": computer_name, "PlayerName": username, "ComputerScore": computer_score, "PlayerScore": human_score}
    print("============================================")
    print("Existing data: {}".format(data))
    data.append(new_data)
    print("New data: {}".format(new_data))
    pickle.dump(data, open("w6_project.p", "wb"))  # Save the data into a pickle file
    print("Saved Data: {}".format(data))
    print("===================================================")
    pass

def info():
    try:
        existing_data = pickle.load(open("w6_project.p", "rb"))
        data.append(existing_data)
    except (OSError, IOError) as e:
        pickle.dump({}, open("w6_project.p", "wb"))
    print("===================================================")
    print("Existing data: {}".format(data))
    print("===================================================")
    pass

def main():
    print("Running info()......\n")
    info()
    print("\nRunning save_score()......\n")
    save_score()

if __name__ == "__main__":
    main()

Answer 1

問題是您有兩個列表 - data和existing_data - 並且您以錯誤的方式加入它們。 使用append()將一個列表放入另一個列表中。 您應該使用extend()加入它們

 data.extend(existing_data)

或更短

 data += existing_data

但是如果你在加載 pickle 后添加新數據，那么你應該簡單地直接賦值給變量

 data = pickle.load(...)

---

編輯：最小工作示例

import pickle

computer_name = "computer name"
username = "user 1"
computer_score = 3
human_score = 1

def save_score():
    
    try:
        data = pickle.load(open("w6_project.p", "rb"))
        print("Inside try: {}".format(data))
    except (OSError, IOError) as e:
        data = []
        
    new_data = {"ComputerName": computer_name, "PlayerName": username, "ComputerScore": computer_score, "PlayerScore": human_score}
    data.append(new_data)

    pickle.dump(data, open("w6_project.p", "wb"))  # Save the data into a pickle file

    print("============================================")
    print("Existing Data: {}".format(data))
    print("New Data: {}".format(new_data))
    print("Saved Data: {}".format(data))
    print("Length Data: {}".format( len(data) ))
    print("===================================================")

def info():
    try:
        data = pickle.load(open("w6_project.p", "rb"))
    except (OSError, IOError) as e:
        data = []
        
    print("===================================================")
    print("Existing Data: {}".format(data))
    print("Length Data: {}".format( len(data) ))
    print("===================================================")

def main():
    print("Running info()......\n")
    info()

    print("\nRunning save_score()......\n")
    save_score()

if __name__ == "__main__":
    main()