[英]Pandas: how to concatenate a MultiIndex DataFrame with a single index DataFrame, and custom ordering
I have a MultiIndex pandas DataFrame df_multi
like:我有一个 MultiIndex pandas DataFrame
df_multi
像:
import pandas as pd
df_multi = pd.DataFrame([['A', 'A1', 0,234,2002],['A', 'A1', 1,324,2550],
['A', 'A1', 2,345,3207],['A', 'A1', 3,458,4560],['A', 'A2', 0,569,1980],
['A', 'A2', 1,657,2314],['A', 'A2', 2,768,4568],['A', 'A2', 3,823,5761]],
columns=['Product','Scenario','Time','Quantity','Price']).set_index(
['Product', 'Scenario'])
and a single index DataFrame df_single
like:和单个索引 DataFrame
df_single
像:
df_single = pd.DataFrame([['A', -3,100],['A', -2,100], ['A', -1,100]],
columns=['Product','Time','Quantity']).set_index(['Product'])
For every 'Product' in the first index level of df_multi
, and for every 'Scenario' in its second level, I would like to append/concatenate the rows in df_single
, which contain some negative 'Time' values to be appended before the positive 'Time' values in df_multi
begin.对于
df_multi
的第一个索引级别中的每个“产品”,以及其第二个级别中的每个“场景”,我想附加/连接df_single
的行,其中包含一些要附加在正值之前的负“时间”值df_multi
“时间”值开始。
I would furthermore like the resulting DataFrame to be first MultiIndexed by ['Product','Scenario'] (just like df_multi
), then secondly with the rows ordered by ascending value of 'Time'.此外,我希望生成的 DataFrame 首先由 ['Product','Scenario'](就像
df_multi
)进行df_multi
,然后按“时间”的升序值对行进行排序。 In other words, the desired result is:换句话说,想要的结果是:
df_result = pd.DataFrame([['A', 'A1', -3,100,'NaN'],['A', 'A1', -2,100,'NaN'],
['A', 'A1', -1,100,'NaN'],['A', 'A1', 0,234,2002],['A', 'A1', 1,324,2550],
['A', 'A1', 2,345,3207],['A', 'A1', 3,458,4560],['A','A2', -3,100,'NaN'],
['A', 'A2', -2,100,'NaN'],['A', 'A2', -1,100,'NaN'],['A', 'A2', 0,569,1980],
['A', 'A2', 1,657,2314],['A', 'A2', 2,768,4568],['A', 'A2', 3,823,5761]],
columns=['Product','Scenario','Time','Quantity','Price']).set_index(
['Product', 'Scenario'])
EDIT:编辑:
df_single
has no 'Scenario' values, which can be confusing. df_single
没有“场景”值,这可能会令人困惑。 As long as 'Product' matches, the same rows of df_single
are to be appended to every scenario in df_multi
, and they simply "inherit" the Scenario values for free.df_single
将被追加到每一个场景df_multi
,他们只是“继承”的情景免费值。 I tried to implement this with all of join
, concat
and merge
, and I did not succeed.我试图用所有的
join
、 concat
和merge
来实现这一点,但我没有成功。 What would be the best way of achieving the desired result?达到预期结果的最佳方法是什么?
Consider resetting indexes as columns for a merge
, followed by a groupby
aggregation only to return one occurrence per group and avoid duplicates.考虑将索引重置为
merge
列,然后是groupby
聚合,只为每组返回一次并避免重复。 Afterwards, run a concatenation, concat
, followed by column sorting and setting back the multi-index.然后,运行串联
concat
,然后进行列排序并设置多索引。
# MERGE AND AGGREGATION
df_temp = df_multi.reset_index().merge(df_single.reset_index(), on='Product', suffixes=['','_'])\
.groupby(['Product', 'Scenario', 'Time_'])['Quantity_'].max()\
.reset_index().rename(columns={'Time_':'Time','Quantity_':'Quantity'})
# ROW BIND CONCATENATION
df_final = pd.concat([df_multi.reset_index(), df_temp])\
.sort_values(['Product','Scenario', 'Time'])\
.set_index(['Product', 'Scenario'])[['Time', 'Quantity', 'Price']]
print(df_final)
# Time Quantity Price
# Product Scenario
# A A1 -3 100 NaN
# A1 -2 100 NaN
# A1 -1 100 NaN
# A1 0 234 2002.0
# A1 1 324 2550.0
# A1 2 345 3207.0
# A1 3 458 4560.0
# A2 -3 100 NaN
# A2 -2 100 NaN
# A2 -1 100 NaN
# A2 0 569 1980.0
# A2 1 657 2314.0
# A2 2 768 4568.0
# A2 3 823 5761.0
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