将编辑后的值更新回原始文件答案

【问题标题】：Updating the edited value back to original file将编辑后的值更新回原始文件
【发布时间】：2020-09-01 15:25:27
【问题描述】：

我有一个文本文件转字典

文本文件：

banana
delicious
yellow

watermelon
big
red

orange
juicy
vitamin c

我要转换的代码是：

file = "C:\\Users\\user\\Downloads\\file.txt" #file path
d= {} 
with open(file, 'r') as f:
    for empty_line, group in itertools.groupby(f, lambda x: x == '\n'): 
        if empty_line:
            continue
        fruit, *desc = map(str.strip, group)
        d[fruit] = desc 
        d= {k.upper():v for k,v in d.items()} #capitalise the names

转换成字典d后：

{'BANANA' : ['delicious', 'yellow'],

'WATERMELON' : ['big', 'red'],

'ORANGE' : ['juicy', 'vitamin c']}

我正在努力将附加值添加到键中，不仅是字典本身，还有原始文件。但是我当前的代码删除了所有键和值，除了我正在添加信息的那个。而且也不把钥匙还给我。

def Add_Info():
    original_name = input("Please enter the name you would like to modify? ").upper()
    additionalinfo = input("Enter information you would like to add? ")
        
    with open(file,'r+') as f:
        data = f.read()
        data = d[original_name].append(additionalinfo)
        f.truncate(0)
        f.seek(0)
        f.write("\n".join(d[original_name]))
        f.close()

for eg, if 
original_name = watermelon
additionalinfo = hard,

in the file, it only returns me 
big  
red
hard

相反，我希望剩余的水果、香蕉和橙子保持不变，只需将值 hard 添加到 watermelon

下的文件中

【问题讨论】：

您（显然）已经拥有将文本文件转换为字典 d 的代码。如果要保留现有内容，您需要更新它，然后用整个字典覆盖整个文件。如果你能弄清楚，请edit你的问题并添加你当前必须将文件转换为字典的代码（所以它是minimal reproducible example）。
我已编辑以包含我的代码。谢谢。
尝试将open(file,'r+') 更改为open(file,'a+')。更多详情请见this SO question
我刚试了，结果还是一样

标签： python python-3.x dictionary key key-value

【解决方案1】：

以下是如何实施我在评论中提出的建议。我还进行了一些其他更改以改进代码并遵循PEP 8 - Style Guide for Python Code 准则：

import itertools

def read_data(file):
    d= {}
    with open(file, 'r') as f:
        for empty_line, group in itertools.groupby(f, lambda x: x == '\n'):
            if empty_line:
                continue
            fruit, *desc = map(str.strip, group)
            d[fruit] = desc
            d= {k.upper():v for k,v in d.items()} #capitalise the names
    return d

def write_data(file, d):
    with open(file, 'w') as f:
        for key, values in d.items():
            f.write(key + '\n')
            for value in values:
                f.write(value + '\n')
            f.write('\n')

def add_info(file):
#    original_name = input("Please enter the name you would like to modify? ").upper()
#    additional_info = input("Enter information you would like to add? ")

    # hardcoded for testing
    original_name = "watermelon".upper()
    additional_info = "hard"

    d = read_data(file)
    d.setdefault(original_name, []).append(additional_info)
    write_data(file, d)


file = 'fruit_info.txt'  #file path
add_info(file)

【讨论】：