上述代码报错invalid literal for int() with base 10: '1.5'

很抱歉，这是因为输入的距离值是浮点数，而代码中使用了int()转换为整数，导致报错。我们可以将这一行代码修改为：

v1, v2, weight = input('请输入存在路径的两个单位以及相通两个单位间的距离(用空格隔开)：').split()
v1, v2, weight = int(v1), int(v2), float(weight)

将weight的类型改为浮点数即可。修改后的完整代码如下：

class Graph:
    def __init__(self, n, e):
        self.n = n
        self.e = e
        self.arc = [[float('inf')]*n for _ in range(n)]
        self.freq = [0]*n
        self.name = ['']*n

    def add_edge(self, v1, v2, weight):
        self.arc[v1][v2] = weight
        self.arc[v2][v1] = weight

    def set_freq(self, v, freq):
        self.freq[v] = freq

    def set_name(self, v, name):
        self.name[v] = name

def floyd(graph):
    n = graph.n
    arc = graph.arc
    for k in range(n):
        for i in range(n):
            for j in range(n):
                if arc[i][j] > arc[i][k] + arc[k][j]:
                    arc[i][j] = arc[i][k] + arc[k][j]
    return arc

n = int(input('请输入图中顶点个数：'))
e = int(input('请输入图中边的条数：'))
t = Graph(n, e)

for i in range(n):
    name = input('请输入第%d个单位的名称：' % (i+1))
    t.set_name(i, name)
    freq = int(input('请输入第%d个单位的去超市的频度：' % (i+1)))
    t.set_freq(i, freq)

for i in range(e):
    v1, v2, weight = input('请输入存在路径的两个单位以及相通两个单位间的距离(用空格隔开)：').split()
    v1, v2, weight = int(v1), int(v2), float(weight)
    t.add_edge(v1, v2, weight*t.freq[v2])

arc = floyd(t)
min_row = float('inf')
min_row_index = 0
for i in range(n):
    row_sum = sum(arc[i])
    if row_sum < min_row:
        min_row = row_sum
        min_row_index = i

print('学校超市最佳选址是：', t.name[min_row_index])

希望这次修改能够解决问题。如果还有其他疑问，欢迎随时提出。