Question

所以我一直试图让这两个功能起作用，当我这样做时，它们工作正常，但是当我使用elif函数组合这两个函数时，它只运行第一个函数并打印出位置列表，并且错误说＆＃34; neighbour_list未定义＆＃34;

这是我的代码

 my_file=open("test_graph_1.txt","r")
 x=[]
 y=[]
 nodenumber=[]
 positionx=[]
 positiony=[]


for row in my_file:

    value=row[:-1]

    my_list=value.split(",")

    if len(my_list)==3:
        nodenumber.append(int(my_list[0]))

        positionx.append(int(my_list[1]))
        positiony.append(int(my_list[2]))

        nodenumber1 =[(nodenumber[a],positionx[a],positiony[a]) for a i range(len(nodenumber))]
        position_list=tuple(nodenumber1)




    elif len(my_list)==2:
        x.append(int(my_list[0]))
        y.append(int(my_list[1]))

        l1 = [(x[i] , y[i]) for i in range(len(x))]
        l2 = [(y[i] , x[i]) for i in range(len(x))]
        l1.extend(l2)
        neighbour_list=[[l[0] for l in l1 if l[1] == j] for j in range(len(x))]


 print("position_list",position_list)
 print("neigh",neighbour_list)

但是当我打印代码时，位置列表很好，但是neighbour_list就像这样：[[4,1]，[0,4,2]，[1,3]，[2,5,4] ]，[3,0,1]，[3]， []] 额外的空字符串，它不是假设在那里但在此之前一切都很好

Answer 1

如果，对于每次循环，my_list[2] != ""为True，则永远不会定义neighbour_list。然后

print("neigh",neighbour_list)

会引发NameError: the neighbour_list is not defined。

相反，请在输入neighbour_list之前定义for-loop。你也可以使用

if len(my_list) == 3:
    ...
elif len(my_list) == 2:
    ...
else:
    ...

处理您希望接收的两种类型的行。

N = 5
position_list = list()
neighbour_list = [list() for j in range(N)]

with open("test_graph_1.txt","r") as my_file:
    for row in my_file:
        try:
            my_list = map(int, row.split(','))
        except ValueError:
            # Choose how to handle malformed lines
            print('invalid line: {!r}'format(row))
            continue
        if len(my_list) == 3:
            nodenumber, positionX, positionY = my_list
            position_list.append(tuple([nodenumber,positionX,positionY]))
        elif len(my_list) == 2:
            nodenumber1, nodenumber2 = my_list
            neighbour_list[nodenumber1].append(nodenumber2)
            neighbour_list[nodenumber2].append(nodenumber1)            
        else:
            # Choose how to handle lines with more than 3 or less than 2 items
            continue

print(position_list)
print("neigh", neighbour_list)

您可能还想使用networkx或igraph等图表库。

使用elif读取文本文件的两个函数

1 个答案: