我有一个python数据框,其距离列出如下
dict = {'from' : ['A','A','A','B','B','D','D','D'],
'to' : ['B','C','D','C','E','B','C','E'],
'distances': [4,3,1,1,3,4,2,9]}
df = pd.DataFrame.from_dict(dict)
我想列举所有距离:
从point1 ==> point2
其中point1 ==> point2 =从point1 ==> B +从B ==> point2并包含在a
中我如何使用python有效地做到这一点-我假设某种pd.merge?
然后我想将数据框重新格式化为以下内容
columns = ['From','To','Distance','Distance via B']
如果您正在寻找长度为3的路线,这是一个解决方案。请注意,在某些情况下,直接路由(例如A到B)比A-B-C路由短:
three_route = pd.merge(df, df, left_on="to", right_on="from")
three_route["distance"] = three_route.distances_x + three_route.distances_y
three_route = three_route[["from_x", "to_x", "to_y", "distance"]]. \
rename(columns = {"from_x":"from", "to_x": "via", "to_y": "to"})
结果是:
from via to distance
0 A B C 5
1 A B E 7
2 D B C 5
3 D B E 7
4 A D B 5
5 A D C 3
6 A D E 10