使用Matplotlib绘制平行坐标系的示例详解

class ParallelCoord:
    """
    平行坐标系
    """
    def __init__(self, title, x_labels, y_labels, y_data, y_min, y_max):
        self.title = title
        self.x_labels = x_labels
        self.y_labels = y_labels
        self.y_data = y_data
        self.y_min = y_min
        self.y_max = y_max

import matplotlib.pyplot as plt
from matplotlib.path import Path
import matplotlib.patches as patches
import numpy as np
class ParallelCoord:
    """
    平行坐标系
    """
    def __init__(self, title, x_labels, y_labels, y_data, y_mins, y_maxs):
        self.title = title
        self.x_labels = x_labels
        self.y_labels = y_labels
        self.y_data = y_data
        self.y_mins = y_mins
        self.y_maxs = y_maxs
    def draw(self):
        # 1. 设置画布
        fig, host = plt.subplots(figsize=(10, 4))
        # 2. 设置标题
        host.set_title(self.title, fontsize=18, pad=12)
        # 3. 设置各个平行的Y轴
        # 每个坐标系的上下限不一样，调整显示方式
        dys = np.array(self.y_maxs) - np.array(self.y_mins)
        zs = np.zeros_like(self.y_data)
        zs[:, 0] = self.y_data[:, 0]
        zs[:, 1:] = (self.y_data[:, 1:] - self.y_mins[1:]) / dys[1:] * dys[
            0
        ] + self.y_mins[0]
        axes = [host] + [host.twinx() for i in range(len(self.y_labels) - 1)]
        for i, ax in enumerate(axes):
            ax.set_ylim(self.y_mins[i], self.y_maxs[i])
            ax.spines["top"].set_visible(False)
            ax.spines["bottom"].set_visible(False)
            if ax != host:
                ax.spines["left"].set_visible(False)
                ax.yaxis.set_ticks_position("right")
                ax.spines["right"].set_position(("axes", i / (len(self.y_labels) - 1)))
        # 4. 设置X轴
        host.set_xlim(0, len(self.y_labels) - 1)
        host.set_xticks(range(len(self.y_labels)))
        host.set_xticklabels(self.y_labels, fontsize=14)
        host.tick_params(axis="x", which="major", pad=7)
        host.spines["right"].set_visible(False)
        host.xaxis.tick_top()
        # 5. 在平行坐标系中绘制曲线
        colors = plt.cm.Set1.colors
        legend_handles = [None for _ in self.x_labels]
        for j in range(len(self.x_labels)):
            verts = list(
                zip(
                    [
                        x
                        for x in np.linspace(
                            0,
                            len(self.y_data) - 1,
                            len(self.y_data) * 3 - 2,
                            endpoint=True,
                        )
                    ],
                    np.repeat(zs[j, :], 3)[1:-1],
                )
            )
            codes = [Path.MOVETO] + [Path.CURVE4 for _ in range(len(verts) - 1)]
            path = Path(verts, codes)
            patch = patches.PathPatch(
                path, facecolor="none", lw=2, alpha=0.7, edgecolor=colors[j]
            )
            legend_handles[j] = patch
            host.add_patch(patch)
        # 6. 绘制图例
        host.legend(
            self.x_labels,
            loc="lower center",
            bbox_to_anchor=(0.5, -0.18),
            ncol=len(self.x_labels),
            fancybox=True,
            shadow=True,
        )
        # 显示图形
        plt.tight_layout()
        plt.show()

#根据示例数据设置变量
title = "学生各科成绩"
x_labels = ["学生A", "学生B", "学生C", "学生D", "学生E"]
y_labels = ["语文", "数学", "英语", "物理", "化学"]
y_data = np.array(
    [
        [100, 120, 98, 88, 78],
        [105, 133, 109, 87, 89],
        [80, 112, 87, 90, 95],
        [90, 89, 76, 89, 88],
        [102, 60, 90, 66, 65],
    ]
)
y_mins = [0, 0, 0, 0, 0]
y_maxs = [120, 150, 110, 90, 100]
#绘制
pc = ParallelCoord(title, x_labels, y_labels, y_data, y_mins, y_maxs)
pc.draw()