Pandas chain.from_iterable:类型为'itertools.chain'的错误对象没有len() [英] Pandas chain.from_iterable: Error object of type 'itertools.chain' has no len()

问题描述

具有如下数据框:

df_data=pd.DataFrame({'name':[['ABC','DOS','TRES'],['XYZ','MORTGAGE','SOLUTIONS']],
                      'original': ['ABC DOS TRES','XYZ MORTGAGE SOLUTIONS']})

我正在使用chain.from_iterable提取列表中的每个项目并将结果添加到数据框中:

I am using chain.from_iterable to extract every item in a list and add the result to a dataframe:

s = pd.DataFrame(chain.from_iterable(df_data['name']),columns=['word'])

我该怎么做?

t = pd.DataFrame({'word': chain.from_iterable(df_data['name'])})

最后一次创建数据框时出现错误TypeError: object of type 'itertools.chain' has no len().两种数据框创建之间有什么区别?如何解决上一次创建中的错误?

The last creation of dataframe is giving an error TypeError: object of type 'itertools.chain' has no len(). What is the difference between both dataframe creations? How the error in the last creation can be fixed?

谢谢:)

推荐答案

使用chain.from_iterable返回一个迭代器，而不是列表/序列.较早版本的Pandas需要传递给数据框构造函数的对象具有len，因此它知道要在后端分配的大小数组. chain对象不提供(也不应该提供).

Using chain.from_iterable returns an iterator, not a list/sequence. Older versions of Pandas needs the objects you pass to the data frame constructor to have a len so it knows what size array to allocate on the backend. The chain object does not supply that (nor should it).

您可以将其包装在list中，以解决您的问题:

You can wrap it in list is solve your issue:

t = pd.DataFrame({'word': list(chain.from_iterable(df_data['name']))})

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