Python：如何从数据帧创建稀疏矩阵？

Question

Using pandas=1.1.5. I just want to convert the below df into a sparse matrix. Sorry if this is trivial. I rarely use sparse matrix. Thanks in advance!

df1 = pd.DataFrame({'Grp': ['3' , '10'],
                   'Rating': ['1', '2']
                   })

Answer 1

You can set the type of the dataframe to a SparseDtype

import pandas as pd

dtype = pd.SparseDtype(int, fill_value=0)
df1 = df1.astype(dtype)

In [15]: df1.dtypes
Out[15]: 
Grp       Sparse[int64, 0]
Rating    Sparse[int64, 0]