如何从Python 3中的磁盘读取和编辑列表？

Question

我有一个字典列表，我想要附加到一个单独的磁盘文件。然后，我希望能够阅读这个字典项目列表，并将它们移到其他列表中，在不同的文件中。

import os

# List 'x' will auto-populate itself with hundreds of new dictionary items upon run - using x.append({'name': f'{var}', 'job': f'{var2}'}) etc.

x = []

i = input('Request: ')

if i == 'add to list':
    with open('example list', 'a') as list:
        list.write(x)
elif i == 'print list':
    with open('example list', 'r') as list:
        list.read(x)
        print(list)

# in this next block, I would like to be able to move an item from the 'example list' list to a different list that is housed in a separate file

elif i == 'move item':
    # 'n' requests an integer value to represent the index in the list
    n = input('Which item do you want to move? ')
    with open('example list', 'r') as list:
        j = list[n]
        # I want to delete 'j' from 'example list' 
    with open('other list', 'a') as other_list:
        # I want to append 'j' to 'other list'
        other_list.write(j)

print('example list')

我被困在阅读和移动这些清单项目。我甚至无法让它以一种很好的格式打印“示例列表”。

我听说过pickle模块，但我从未使用过它。我还了解到，可能需要将这些列表保存为json文件，以便能够在其中访问列表项和随后的字典键。

Answer 1

我想通了。使用json模块，我能够将列表转储到外部json文件中：

x = []

with open('json list.json', 'w') as f:
    json.dump(x, f)

然后，我可以用以下内容加载数据：

list1 = open('json list', 'r')
listread = list1.read()
data = json.loads(listread)

对于在列表之间移动项目，我使用了以下方法：

move_item = data[3]
del move_item
json.dumps(data)
move_to = open('other list'. 'a')
move_to.write(move_item)
list1.close()
move_to.close()

加载后，列表和随后的字典作为各自的对象保持不变，从而允许通过索引或键进行访问。谢谢大家，我用了大家的建议。

Answer 2

我认为你在这里有一个误解，因为列表不会将内容转换为列表。就像变量一样。我已经更改了你代码的某些部分。我不知道它是否会工作，因为你没有指定任何输入或输出。看一看

if i == 'add to list':
    with open('example list', 'a') as f:
        # append whatever there is in 'x' into 'example list'
        f.write(x)
elif i == 'print list':
    with open('example list', 'r') as f:
        file_content=f.read()
        print(file_content)

# in this next block, I would like to be able to move an item from the 'example list' list to a different list that is housed in a separate file

elif i == 'move item':
    # 'n' requests an integer value to represent the index in the list
    n = input('Which item do you want to move? ')
    with open('example list', 'r') as f:
        # .readlines() would return a list of lines from 'example list'
        file_lines = f.readlines()
        # pop line with index 'n'
        j = file_lines.pop(n)
        # I want to delete 'j' from 'example list' 
    with open('other list', 'a') as other_list:
        # I want to append 'j' to 'other list'
        other_list.write(j)

print('example list')