小编use*_*041的帖子

我正在尝试编写Dijkstra的算法,但我正在努力解决如何在代码中"说出"某些事情.为了可视化,这里是我想要使用数组表示的列:

   max_nodes  
   A  B  C         Length       Predecessor       Visited/Unvisited
A 0  1   2             -1                                              U
B 1  0   1             -1                                              U
C 2  1   0             -1                                              U

所以,会有几个数组,如下面的代码所示:

def dijkstra (graph, start, end)

network[max_nodes][max_nodes]
state  [max_nodes][length]
state2 [max_nodes][predecessor]
state3 [max_nodes][visited]
initialNode = 0

    for nodes in graph:
      D[max_nodes][length] = -1
      P[max_nodes][predecessor] = ""
      V[max_nodes][visited] = false

      for l in graph:

       length = lengthFromSource[node] + graph[node][l]
          if length < lengthFromSourceNode[w]:
             state[l][length] = x
             state2[l][predecessor] 
             state3[l][visited] = true
          x +=1

粗体部分是我坚持的地方 - 我正在尝试实现算法的这一部分: …

我收到错误'对象引用没有设置为对象的实例'.我试过看类似的问题,但真的看不出我的程序有什么问题.我遇到错误的代码行是:

labelQuestion.Text = table.Rows[0]["Question"].ToString();

这是我的完整代码:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Data.Sql;
using System.Data.SqlClient;

namespace Quiz_Test
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    String chosenAnswer, correctAnswer;
    DataTable table;

    private void Form1_Load(object sender, EventArgs e)
    {
        //declare connection string using windows security
        string cnString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\Users\\Hannah\\Desktop\\QuizQuestions.accdb";

        //declare Connection, command and other related objects
        OleDbConnection conGet = new OleDbConnection(cnString);
        OleDbCommand cmdGet = …

我的代码有两个问题 - 我不知道如何将我的populateArray函数与我的main函数链接; 我不确定我需要传递什么参数另外,我一直在打开要打开的文件的文件路径 - 路径是正确的,文件存在数据.这是我的代码:

network = []  

def populateArray():
    file = open('theroute.txt', 'r')
    network = []  

    for line in file:

        network.append(line)

    print "Network = "
    print network

    file.close()

def main():    
    if __name__ == "__main__":
       populateArray()

任何帮助,将不胜感激!

感谢您的回复 - 我的代码现在看起来像上面,但当我删除def main()时:我收到以下错误:

File "populateArray.py", line 18
    if __name__ == "__main__":
                             ^
IndentationError: unindent does not match any outer indentation level