将 Pandas SparseDataframe 转换为 Scipy 稀疏 csc_matrix [英] Convert Pandas SparseDataframe to Scipy sparse csc_matrix

问题描述

我想将熊猫 SparseDataFrame 转换为 scipy.sparse.csc_matrix.但我不想先把它转换回稠密矩阵.

I want to convert a pandas SparseDataFrame to a scipy.sparse.csc_matrix. But I don't want to convert it back to a dense matrix first.

现在我有类似下面的内容.

Right now I have something like the below.

df = pd.get_dummies(df, sparse=True)

基本上我需要的是从 df 进一步得到一个 scipy.sparse.csc_matrix.有办法吗?

Basically what I need is to further get a scipy.sparse.csc_matrix from df. Is there a way to do it?

推荐答案

感谢@hpaulj 的回复.我最终使用了 https://stackoverflow.com/a/38157234/7298911 中的模板.

Thanks to @hpaulj's reply. I ended it up using the template from https://stackoverflow.com/a/38157234/7298911.

这是修改后的实现.

def sparseDfToCsc(df):
    columns = df.columns
    dat, rows = map(list,zip(*[(df[col].sp_values-df[col].fill_value, df[col].sp_index.to_int_index().indices) for col in columns]))
    cols = [np.ones_like(a)*i for (i,a) in enumerate(dat)]
    datF, rowsF, colsF = np.concatenate(dat), np.concatenate(rows), np.concatenate(cols)
    arr = sparse.coo_matrix((datF, (rowsF, colsF)), df.shape, dtype=np.float64)
    return arr.tocsc()

df = pd.get_dummies(df, sparse=True)
cscMatrix = sparseDfToCsc(df)

这篇关于将 Pandas SparseDataframe 转换为 Scipy 稀疏 csc_matrix的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！