Pandas MultiIndex：将所有列除以一列
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Pandas MultiIndex: Divide all columns by one column
提问by FooBar
I have a data frame resultsof the form
我有一个results表单的数据框
TOTEXPPQ TOTEXPCQ FINLWT21
year quarter
13 1 9.183392e+09 5.459961e+09 1271559.398
2 2.907887e+09 1.834126e+09 481169.672
and I was trying to divide all (the first two) columns by the last one. My attempt was
我试图将所有（前两列）列除以最后一列。我的尝试是
weights = results.pop('FINLWT21')
results/weights
But I get
但我得到
ValueError: cannot join with no level specified and no overlapping names
Which I don't get: There are overlapping names in the index:
我没有得到：索引中有重叠的名称：
weights.head()
year quarter
13 1 1271559.398
2 481169.672
Is there perhaps a better way to do this division? Do I needto reset the index?
也许有更好的方法来进行这种划分？我需要重置索引吗？
回答by Andy Hayden
You have to specify the axis for the divide (with the divmethod):
您必须指定除法轴（使用div方法）：
In [11]: results.div(weights, axis=0)
Out[11]:
TOTEXPPQ TOTEXPCQ
year quarter
13 1 7222.149445 4293.909517
2 6043.371329 3811.807158
The default is axis=1 and the result columnsand weights' index names do not overlap, hence the error message.
默认值为 axis=1 并且结果列和权重的索引名称不重叠，因此会出现错误消息。
