用python写字典

Question

from random import randint    
import threading              
import numpy as np



def gen_write():
    threading.Timer(10.0, gen_write).start()  
    with open("pins.npy", "w") as f:
        f.close()

    data = {}
    for x in range(5):
        pin = randint(99, 9999)
        pins_for_file = pin
        with open('pins.npy', 'a') as f:
            data[x + 1] = pins_for_file
            np.save(f, data)



gen_write()

所以，这就是问题所在，我使用 numpy 将字典写入文件，但不知何故，它只保存了第一个，我已经更改了数十次 for 循环，但我无法获得正确的循环，在至少我认为问题来自那里。 顺便说一句，我是 python 新手。

提前致谢 问候

Answer 1

首先，您可以在循环外打开文件，而不是在循环内打开文件。
其次，您不需要使用with 语句显式关闭您打开的文件，这是使用with 的重点之一。
所以我设想的代码修改如下：

import threading
from sys import getsizeof
from random import randint
import numpy as np

def gen_write():
    #threading.Timer(10.0, gen_write).start()
    data = {}
    with open("pins.npy", "w") as f:
        for x in range(5):
            pin = randint(99, 9999)
            pins_for_file = pin
            data[x+1] = pins_for_file

        np.save(f, data)

gen_write()  

或者更好的是使用 python pickle 模块来保存字典，所以：

import threading
from sys import getsizeof
from random import randint
import pickle

def gen_write():
    #threading.Timer(10.0, gen_write).start()
    data = {}
    with open("pins.pkl", "w") as f:
        for x in range(5):
            pin = randint(99, 9999)
            pins_for_file = pin
            data[x+1] = pins_for_file

        pickle.dump(data, f, pickle.HIGHEST_PROTOCOL)

gen_write()

另外，我评论了threading.Timer(10.0, gen_write).start()，因为我花了很长时间才为我竞选。
另一种方法是将字典保存在 json 文件中，这是一种常用的文件格式。为此，您将执行以下操作：

import threading
from sys import getsizeof
from random import randint
import json

def gen_write():
    #threading.Timer(10.0, gen_write).start()
    data = {}
    with open("pins.json", "w") as f:
        for x in range(5):
            pin = randint(99, 9999)
            pins_for_file = pin
            data[x+1] = pins_for_file

        json.dump(data, f)

gen_write()