使用dict理解时如何避免丢失键的错误 [英] How to avoid error on missing keys when using dict comprehension

问题描述

如何忽略pd.DataFrame.from_dict理解迭代中的缺失键?

How do I ignore missing keys in a pd.DataFrame.from_dict comprehension iteration?

@jezrael在此回答了我用字典值制作df的问题:

@jezrael kindly answered my problem on making a df with dictionary values here:

https://stackoverflow.com/a/49072184/9242601

但是我遇到了Key Error: 'fees'错误，因为不是所有的"Customers"都有一个"fees"键，所以我希望迭代不只是产生一个错误，而是继续到下一个Customer，而不是记录该客户在df中.

But I encountered a Key Error: 'fees' error because not all "Customers" have a 'fees' key, so rather than generating an error, I'd like the iteration to just move on to the next Customer and not record that customer in the df.

我仍然需要一个数据框，因此try... except和if key in dict将不起作用，因为我最终将得到一个空的(或不存在的)df.

I still need a dataframe, so try... except and if key in dict won't work, because I will just end up with an empty (or non-existent) df.

将这个问题有效地推广到两个问题的歉意，但我认为不值得重复完整的初始问题(因此链接).

Apologies for effectively spreading this question over two questions, but I didn't think it was worth repeating the complete initial question (hence the link).

谢谢.

推荐答案

链接没问题-它在Stackoverflow中，没有任何作用.

The link's OK - it's in Stackoverflow and isn't going anywhere.

满足dict.get方法.通过序言，这几乎是您需要了解的所有内容:

Meet the dict.get method. By way of a pre-amble, this is almost everything you need to know about it:

>>> d = {'present': 'real_value'}
>>> d.get('present')
'real_value'
>>> d.get('absent') is None
True
>>> d.get('absent', 'default')
'default'

您应该发现修改后的理解力

You should find that the modified comprehension

{k: dict(v['fees']) for k, v in d.items() if v.get('fees') is not None}

满足您的需求，但这是未经测试的代码.

serves your needs, but this is untested code.

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