[英]get both unique count and max in group-by of pandas dataframe
Using Pandas data frame group by feature and I want to group by column c_b
and (1) calculate unique count for column c_a
and column c_c
, (2) and get the max value of column c_d. 使用Pandas数据帧按功能分组,我想按列c_b
,(1)计算列c_a
和列c_c
唯一计数,(2)并获取列c_d的最大值。 Wondering if there is any solution to write one line of group by code to achieve both goals? 想知道是否有解决方案可以按代码编写一行代码来实现两个目标? I tried the following line of code, but it seems not correct. 我尝试了以下代码行,但似乎不正确。
sampleGroup = sample.groupby('c_b')(['c_a', 'c_d'].agg(pd.Series.nunique), ['c_d'].agg(pd.Series.max))
My expected results are, 我的预期结果是
Expected results , 预期结果 ,
c_b,c_a_unique_count,c_c_unique_count,c_d_max
python,2,2,1.0
c++,2,2,0.0
Thanks. 谢谢。
Input file , 输入文件
c_a,c_b,c_c,c_d
hello,python,numpy,0.0
hi,python,pandas,1.0
ho,c++,vector,0.0
ho,c++,std,0.0
go,c++,std,0.0
Source code , 源代码
sample = pd.read_csv('123.csv', header=None, skiprows=1,
dtype={0:str, 1:str, 2:str, 3:float})
sample.columns = pd.Index(data=['c_a', 'c_b', 'c_c', 'c_d'])
sample['c_d'] = sample['c_d'].astype('int64')
sampleGroup = sample.groupby('c_b')(['c_a', 'c_d'].agg(pd.Series.nunique), ['c_d'].agg(pd.Series.max))
results.to_csv(sampleGroup, index= False)
You can pass a dict to agg()
: 您可以将字典传递给agg()
:
df.groupby('c_b').agg({'c_a':'nunique', 'c_c':'nunique', 'c_d':'max'})
If you don't want c_b
as index, you can pass as_index=False
to groupby
: 如果您不希望c_b
作为索引,则可以将as_index=False
传递给groupby
:
df.groupby('c_b', as_index=False).agg({'c_a':'nunique', 'c_c':'nunique', 'c_d':'max'})
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