[英]Creating multiple new columns in a multiindexed pandas dataframe
Is it possible to create more than one new column in Pandas when a dataframe is multiindexed? 当数据帧是多索引时,是否可以在Pandas中创建多个新列? I would like to add a two new columns
one
and two
under the bar2
supercolumn. 我想补充一两个新列
one
和two
下bar2
supercolumn。 Like so... 像这样......
import pandas as pd
import numpy as np
arrays = [['bar', 'bar', 'baz', 'baz', 'foo', 'foo'],
['one', 'two', 'one', 'two', 'one', 'two']]
index = pd.MultiIndex.from_arrays(arrays, names=['first', 'second'])
df = pd.DataFrame(np.random.randn(3, 6), index=[1, 2, 3], columns=index)
df["bar2", ["one", "two"]] = np.random.randn(3, 2)
I know I can create them one by one using 我知道我可以逐个创建它们
df["bar2", "one"] = np.random.randn(3,1)
df["bar2", "two"] = np.random.randn(3,1)
Is there a quicker way of doing both at the same time? 有没有更快的方法同时做两件事?
In [270]:
df_to_add = pd.DataFrame(np.random.randn(3,2) , columns=[['bar2' , 'bar2'] , ['one' , 'two']] , index = [1 , 2 , 3])
df_to_add
Out[270]:
bar2
one two
1 0.119730 -0.265579
2 1.777329 -1.178128
3 -2.700409 0.457430
In [271]:
pd.concat([df , df_to_add] , axis = 1)
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