Python Pandas : pivot table with aggfunc = count unique distinct
Do you mean something like this?
In [39]: df2.pivot_table(values='X', rows='Y', cols='Z',
aggfunc=lambda x: len(x.unique()))
Out[39]:
Z Z1 Z2 Z3
Y
Y1 1 1 NaN
Y2 NaN NaN 1
Note that using len
assumes you don't have NA
s in your DataFrame. You can do x.value_counts().count()
or len(x.dropna().unique())
otherwise.
This is a good way of counting entries within .pivot_table
:
df2.pivot_table(values='X', index=['Y','Z'], columns='X', aggfunc='count')
X1 X2
Y Z
Y1 Z1 1 1
Z2 1 NaN
Y2 Z3 1 NaN
Since at least version 0.16 of pandas, it does not take the parameter "rows"
As of 0.23, the solution would be:
df2.pivot_table(values='X', index='Y', columns='Z', aggfunc=pd.Series.nunique)
which returns:
Z Z1 Z2 Z3
Y
Y1 1.0 1.0 NaN
Y2 NaN NaN 1.0