如何在Matplotlib中将x轴刻度与刻度标签向上移动并支持自定义调整

可以通过新增可配置的偏移参数，同步调整x轴刻度和标签的垂直位置，具体修改如下：

修改点说明 #

• 在CircleHeatmap类的初始化参数中新增x_tick_offset，数值为正代表向上偏移的幅度，默认值为0即不偏移
• 在labels方法中补充偏移逻辑，可根据需求同时调整刻度线与标签的y轴位置

完整修改后代码 #

import matplotlib.pyplot as plt
import matplotlib.colors as mcl
import numpy as np
import pandas as pd
from typing import List, T
from random import uniform
def l_flatten(l: List[T]) -> List[T]:
    return [j for i in l for j in i]
def get_luminance(color: str) -> float:
    # taken from Seaborn's utils
    rgb = mcl.colorConverter.to_rgba_array(color)[:, :3]
    rgb = np.where(rgb <= .03928, rgb / 12.92, ((rgb + .055) / 1.055) ** 2.4)
    lum = rgb.dot([.2126, .7152, .0722])
    try:
        lum = lum.item()
    except ValueError:
        pass
    return lum
class CircleHeatmap:
    def __init__(self,
                 ax: plt.Axes,
                 df: pd.DataFrame,
                 colors: List[str],
                 annot_show: bool,
                 annot_size: float,
                 circle_size: float,
                 x_labels: List[str],
                 x_labels_size: float,
                 x_labels_color: str,
                 y_labels: List[str],
                 y_labels_size: float,
                 y_labels_color: str,
                 x_tick_offset: float = 0.0) -> None:
        # pass user-provided variables
        self.ax = ax
        self.df = df
        self.colors = colors
        self.annot_show = annot_show
        self.annot_size = annot_size
        self.circle_size = circle_size
        self.x_labels = x_labels
        self.x_labels_size = x_labels_size
        self.x_labels_color = x_labels_color
        self.y_labels = y_labels
        self.y_labels_size = y_labels_size
        self.y_labels_color = y_labels_color
        self.x_tick_offset = x_tick_offset
        # pass technical variables
        self.y_size, self.x_size = self.df.shape
        self.x_arr, self.y_arr = np.meshgrid(np.arange(self.x_size),
                                             np.arange(self.y_size))
        self.x_arr, self.y_arr = ((self.x_arr + 0.5).flat,
                                  (self.y_arr + 0.5).flat)
        self.x_len, self.y_len = [np.linspace(0, len(i), len(i) + 1)[:-1] + 0.5
                                  for i in (self.x_labels, self.y_labels)]
        self.df_values = l_flatten(self.df.values.tolist())
    def plot(self) -> None:
        self.ax.scatter(self.x_arr, self.y_arr,
                        s = self.circle_size ** 2,
                        c = self.colors)
    def labels(self) -> None:
        self.ax.set_xticks(self.x_len)
        self.ax.set_yticks(self.y_len)
        self.ax.set_xticklabels(self.x_labels, fontsize = self.x_labels_size,
                           color = self.x_labels_color)
        self.ax.set_yticklabels(self.y_labels, fontsize = self.y_labels_size,
                           color = self.y_labels_color)
        # 调整x轴标签向上偏移
        for xtick in self.ax.get_xticklabels():
            xtick.set_y(xtick.get_position()[1] + self.x_tick_offset)
        # 如果需要显示刻度线并同步偏移，可取消下面一行的注释
        # self.ax.tick_params(axis='x', offset=self.x_tick_offset * 72)
def main() -> None:
    fig, ax = plt.subplots(figsize = (20, 30))
    df = pd.DataFrame([[uniform(0, 1) for j in range(20)] for i in range(30)])
    colors = ["#EC4E20", "#FF9505", "#016FB9"] * 200
    heatmap = CircleHeatmap(ax = ax,
                            df = df,
                            colors = colors,
                            annot_show = False,
                            annot_size = 16,
                            circle_size = 45,
                            x_labels = [i for i in range(20)],
                            x_labels_size = 20,
                            x_labels_color = "black",
                            y_labels = [i for i in range(30)],
                            y_labels_size = 20,
                            y_labels_color = "black",
                            x_tick_offset = 0.2) # 可自行调整该数值控制上移幅度
    heatmap.plot()
    heatmap.labels()
    for i in ["top", "bottom", "right", "left"]:
        ax.spines[i].set_visible(False)
    plt.savefig("test2.png")
if __name__ == "__main__":
    main()

调整方法 #

你可以修改实例化CircleHeatmap时传入的x_tick_offset数值，数值越大上移幅度越大，比如可尝试0.1、0.3等数值，直到位置符合预期。

内容的提问来源于stack exchange，提问作者Gleb Ryabov