这里有一个方法 -
lens = np.array([len(i) for i in adj_list])
col_idx = np.concatenate(adj_list)
out = np.zeros((len(lens), col_idx.max()+1))
row_idx = np.repeat(np.arange(len(lens)), lens)
vals = np.repeat(1.0/lens, lens)
out[row_idx, col_idx] = vals
样品输入,输出 -
In [494]: adj_list = [np.array([0,2]),np.array([0,1,4])]
In [496]: out
Out[496]:
array([[ 0.5 , 0. , 0.5 , 0. , 0. ],
[ 0.33333333, 0.33333333, 0. , 0. , 0.33333333]])
稀疏矩阵输出
此外,如果你想节省内存并创建稀疏矩阵代替,这是一个简单的扩展 -
In [506]: from scipy.sparse import csr_matrix
In [507]: csr_matrix((vals, (row_idx, col_idx)), shape=(len(lens), col_idx.max()+1))
Out[507]:
<2x5 sparse matrix of type '<type 'numpy.float64'>'
with 5 stored elements in Compressed Sparse Row format>
In [508]: _.toarray()
Out[508]:
array([[ 0.5 , 0. , 0.5 , 0. , 0. ],
[ 0.33333333, 0.33333333, 0. , 0. , 0.33333333]])
'adj_list'的数组元素是否总是采用该序列格式 - '[0,1,2 ...]'? – Divakar
@Divakar他们按升序排列。但是,它们很稀疏 – bordeo