Python 如何将邻接表转换为邻接矩阵

Question

我有一个这样的邻接表：

第一行表示 0 与 1、4 和 5 相邻；第二行表示 1 与 0、2 和 6 相邻；第三行说 2 与 1、3 和 7 相邻，...

如何将它转换成这样的邻接矩阵？

0 1 0 0 1 1 0 0 0 0
1 0 1 0 0 0 1 0 0 0
0 1 0 1 0 0 0 1 0 0
0 0 1 0 1 0 0 0 1 0
1 0 0 1 0 0 0 0 0 1
1 0 0 0 0 0 0 1 1 0
0 1 0 0 0 0 0 0 1 1
0 0 1 0 0 1 0 0 0 1
0 0 0 1 0 1 1 0 0 0
0 0 0 0 1 0 1 1 0 0

Answer 1

import numpy as np
adj_dict = {}
path_to_list = '../adj_list.txt'
# Replace with zero if vertices are connected to themselves
empty_digonal = 1
with open(path_to_list) as f:
    adj_dict = {int(line.split()[0]):[int(x) for x in line.split()[empty_diagonal:]] for line in f.read().strip('\n').splitlines()}
adj_mx = np.zeros([len(adj_dict),len(adj_dict)])
for i in adj_dict:
        adj_mx[i,adj_dict[i]] = 1
assert sum(sum(adj_mx - adj_mx.T)) == 0, 'The matrix is not symmetric'

可能不是最佳解决方案，但它有效

Answer 2

如何在数据帧内创建相同长度的定位 0 和 1 列表，然后将它们作为系列拉出。

# the lists will all be this length
maxlen = df.max().max()

df = pd.DataFrame([
    [0, 1, 4, 5],
    [1, 0, 2, 6],
    [2, 1, 3, 7],
    [3, 2, 4, 8],
    [4, 0, 3, 9],
    [5, 0, 7, 8],
    [6, 1, 8, 9],
    [7, 2, 5, 9],
    [8, 3, 5, 6],
    [9, 4, 6, 7]])

# the function used to create the lists
def createlist(x):
    arr=(maxlen+1)*[0]
    arr[x]=1
    return arr

# create the list for each cell, then concatenate the lists per row vertically, sum them, giving each final row
df2 = df.applymap(createlist).apply(lambda x: pd.concat([pd.Series(x[i]) for i in range(len(df.columns))], axis=1).sum(axis=1),axis=1)


df2

    0   1   2   3   4   5   6   7   8   9
0   1   1   0   0   1   1   0   0   0   0
1   1   1   1   0   0   0   1   0   0   0
2   0   1   1   1   0   0   0   1   0   0
3   0   0   1   1   1   0   0   0   1   0
4   1   0   0   1   1   0   0   0   0   1
5   1   0   0   0   0   1   0   1   1   0
6   0   1   0   0   0   0   1   0   1   1
7   0   0   1   0   0   1   0   1   0   1
8   0   0   0   1   0   1   1   0   1   0
9   0   0   0   0   1   0   1   1   0   1

要将对角线设置为零，请执行以下操作：

df3 = df2.values

np.fill_diagonal(df3, 0)

Answer 3

import numpy as np

rows = (
    [0, 1, 4, 5],
    [1, 0, 2, 6],
    [2, 1, 3, 7],
    [3, 2, 4, 8],
    [4, 0, 3, 9],
    [5, 0, 7, 8],
    [6, 1, 8, 9],
    [7, 2, 5, 9],
    [8, 3, 5, 6],
    [9, 4, 6, 7]
)

matrix = np.zeros((10,10))
for row in rows:
    matrix[row[0],row[1:]] = 1
print(matrix)

Python 如何将邻接表转换为邻接矩阵

How to convert an adjacency list into an adjacency matrix in Python

python

adjacency-list

adjacency-matrix

python-3.x