Pandas“只能比较标记相同的 DataFrame 对象"错误 [英] Pandas "Can only compare identically-labeled DataFrame objects" error

问题描述

我正在使用 Pandas 来比较加载到两个数据帧(uat、prod)中的两个文件的输出:...

I'm using Pandas to compare the outputs of two files loaded into two data frames (uat, prod): ...

uat = uat[['Customer Number','Product']]
prod = prod[['Customer Number','Product']]
print uat['Customer Number'] == prod['Customer Number']
print uat['Product'] == prod['Product']
print uat == prod

The first two match exactly:
74357    True
74356    True
Name: Customer Number, dtype: bool
74357    True
74356    True
Name: Product, dtype: bool

对于第三次打印，我收到一个错误:只能比较标记相同的 DataFrame 对象.如果前两个比较好，那么第三个有什么问题?

For the third print, I get an error: Can only compare identically-labeled DataFrame objects. If the first two compared fine, what's wrong with the 3rd?

谢谢

推荐答案

这里有一个小例子来说明这一点(它只适用于 DataFrames，不适用于 Series，直到 Pandas 0.19 才适用于两者):

Here's a small example to demonstrate this (which only applied to DataFrames, not Series, until Pandas 0.19 where it applies to both):

In [1]: df1 = pd.DataFrame([[1, 2], [3, 4]])

In [2]: df2 = pd.DataFrame([[3, 4], [1, 2]], index=[1, 0])

In [3]: df1 == df2
Exception: Can only compare identically-labeled DataFrame objects

一种解决方案是对索引进行排序 首先(注意:某些函数需要排序索引):

One solution is to sort the index first (Note: some functions require sorted indexes):

In [4]: df2.sort_index(inplace=True)

In [5]: df1 == df2
Out[5]: 
      0     1
0  True  True
1  True  True

注意:== 也对列的顺序，因此您可能必须使用sort_index(axis=1):

Note: == is also sensitive to the order of columns, so you may have to use sort_index(axis=1):

In [11]: df1.sort_index().sort_index(axis=1) == df2.sort_index().sort_index(axis=1)
Out[11]: 
      0     1
0  True  True
1  True  True

注意:这仍然可以引发(如果排序后索引/列的标签不同).

Note: This can still raise (if the index/columns aren't identically labelled after sorting).

这篇关于Pandas“只能比较标记相同的 DataFrame 对象"错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！