如何绘制含字符串/整数类型节点ID的多路线图？解决索引错误

给定以下数据：

all_Ids = ["01", "02", 1, 2, 3, 4, 5]
all_xs = [12, 50, 36, 81, 70, 66, 34]
all_ys = [41, 50, 97, 22, 11, 89, 33]
Routes = [["01", 2, 3, "01"], ["02", 1, "02"], ["01", 4, "01"], ["02", 5, "02"]]

其中all_Ids包含字符串和整数类型的节点ID，all_xs/all_ys是对应节点的坐标；Routes是闭合路线列表。编写的绘图函数SolutionPlot在调用时触发错误：

IndexError: arrays used as indices must be of integer (or boolean) type

原函数代码：

def SolutionPlot(xx, yy, all_ids, RoutesContainer):
    fig, ax = plt.subplots()
    fig.set_size_inches(6, 6)
    allxs = np.array(xx) 
    allys = np.array(yy)
    for v in RoutesContainer:
        final_route = v
        final_route = np.array(final_route) 

        ax.plot(allxs[final_route], allys[final_route], ls="-", marker="o", markersize=8)

    plt.xlim([0, 100])
    plt.ylim([0, 100])
    plt.title("Vehicle Routing Problem (Clarke & Wright Heuristic)")

    for xi, yi, pidi in zip(xx, yy, all_ids):
        ax.annotate(str(pidi), xy=(xi,yi), fontsize = 13)

    fig = plt.gcf()
    fig.set_size_inches(8, 8)
    
    plt.style.use('seaborn-dark-palette')  
    plt.show()

错误原因 #

allxs和allys是NumPy数组，而final_route中混合了字符串（如"01"）和整数ID。NumPy数组要求索引必须是整数或布尔类型，用字符串直接索引会触发IndexError。同时调用函数时存在参数笔误：原变量是all_xs、all_ys、all_Ids，但调用时写的是allxs、allys、allIds，需要修正。

解决方案 #

先建立ID到数组索引的映射字典，将路线中的每个ID转换为对应的坐标列表索引，再用索引获取坐标绘图。修改后的函数如下：

import numpy as np
import matplotlib.pyplot as plt

def SolutionPlot(xx, yy, all_ids, RoutesContainer):
    # 建立ID到索引的映射：同时处理字符串和整数类型的ID
    id_to_index = {}
    for idx, id_val in enumerate(all_ids):
        # 为字符串ID和整数ID分别建立映射
        id_to_index[id_val] = idx
        id_to_index[str(id_val)] = idx
    
    fig, ax = plt.subplots()
    fig.set_size_inches(6, 6)
    allxs = np.array(xx) 
    allys = np.array(yy)
    
    for v in RoutesContainer:
        # 将路线中的每个ID转换为对应的索引
        route_indices = [id_to_index[id_val] for id_val in v]
        route_indices = np.array(route_indices)
        
        ax.plot(allxs[route_indices], allys[route_indices], ls="-", marker="o", markersize=8)

    plt.xlim([0, 100])
    plt.ylim([0, 100])
    plt.title("Vehicle Routing Problem (Clarke & Wright Heuristic)")

    for xi, yi, pidi in zip(xx, yy, all_ids):
        ax.annotate(str(pidi), xy=(xi,yi), fontsize = 13)

    fig = plt.gcf()
    fig.set_size_inches(8, 8)
    
    plt.style.use('seaborn-dark-palette')  
    plt.show()

# 修正参数名后调用函数
SolutionPlot(all_xs, all_ys, all_Ids, Routes)

关键修改点 #

• 创建id_to_index字典，为每个ID（无论字符串还是整数类型）建立到坐标索引的映射，确保路线中的ID能正确转换为数组索引。
• 遍历路线时，将每个ID转换为对应的索引，再用索引访问NumPy数组获取坐标。
• 修正调用函数时的参数名错误，与原始变量名保持一致。

内容的提问来源于stack exchange，提问作者Yannis_Tr