Python:从Python字典中删除空列表的一种优雅方法 [英] Python: An elegant way to delete empty lists from Python dictionary

问题描述

我有一个字典，如:

default = {'a': ['alpha'], 'b': ['beta','gamma'], 'g': []}

我希望消除以下空白值:

I wish to eliminate the empty values as:

default = {'a': ['alpha'], 'b': ['beta','gamma']}

我写了一个函数(下面是在网上找到的一个例子)

I wrote a function (following an example found on the web)

def remove_empty_keys(d):
    for k in d.keys():
        try:
            if len(d[k]) < 1:
                del[k]
        except:
            pass
        return(d)

我有以下问题:

1-我没有找到错误，为什么它总是在以下情况下返回-

1- I didn't find the mistake why it always returns following -

remove_empty_keys(default)
 {'a': ['alpha'], 'b': ['beta'], 'g': []}

2-是否有内置函数可以在不创建原始字典副本的情况下从Python字典中消除/删除Null/None/empty值?

2- Is there a built-in function to eliminate/delete Null/None/empty values from Python dictionary without creating a copy of the original dictionary?

推荐答案

要修复您的功能，请将del[k]更改为del d[k].无法删除字典中的值.

To fix your function, change del[k] to del d[k]. There is no function to delete values in place from a dictionary.

您正在做的是删除变量k，完全不更改字典.这就是为什么总是返回原始词典的原因.

What you are doing is deleting the variable k, not changing the dictionary at all. This is why the original dictionary is always returned.

重写后，您的函数可能如下所示:

Rewritten, your function might look like:

def remove_empty_keys(d):
    for k in d.keys():
        if not d[k]:
            del d[k]

这假定您要消除空列表和None值，并实际上删除具有"false"值的任何项目.

This assumes you want to eliminate both empty list and None values, and actually removes any item with a "false" value.

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