如何从 Python 3 中的磁盘读取和编辑列表？

Question

I have a list of dictionaries that I want to append to a separate disk file. Then, I want to be able to read this list of dictionary items and move them to other lists, in different files.

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')

I am stuck on reading and moving these list items. I can't even get it to print "example list" in a nice format.

I have heard of pickle module, but I've never used it. I also understand that it may be necessary to save these lists as json files in order to be able to access the list items and the subsequent dictionary keys within.

Answer 1

I think you have a misconception here as list does not convert the content into a list. It's like a variable. I have changed some parts of your code. I dont know if it would work as you didn't specify any inputs or outputs. have a look

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')

Answer 2

I figured it out. Using the json module I was able to dump the list to an external json file with:

x = []

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

I could then load the data back in with:

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

For moving items between lists I used this:

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()

Once loaded, the list and subsequent dictionaries within remain intact as their respective objects, thus allowing for access via index or key. Thank you to everyone, I used a combo of everyone's suggestions.