如何设置Matplotlib柱状图的顶部、右侧、底部及左侧坐标轴颜色

需求说明 #

我已使用Python和Matplotlib成功创建柱状图，完成了柱子背景色、柱内数值颜色、x轴与y轴刻度标签颜色的设置。现需实现以下两项调整：

• 将顶部和右侧坐标轴边框设为隐藏
• 将底部（x轴）和左侧（y轴）坐标轴边框设为灰色

当前效果 #

目标效果 #

修改后的完整代码 #

#
# File: bar.py
# Version 1
# License: https://opensource.org/licenses/GPL-3.0 GNU Public License
#

import matplotlib
import matplotlib.pyplot as plt


def bar(category_labels: list = ["A", "B", "C", "D"],
        category_labels_color: str = "grey",
        data: list = [3, 8, 1, 10],
        bar_background_color: str = "red",
        bar_text_color: str = "white",
        direction: str = "vertical",
        x_labels_rotation: int = 0,
        figsize: tuple = (18, 5),
        file_path: str = ".",
        file_name: str = "bar.png"):
    """
    Documentation: https://matplotlib.org/stable/gallery/lines_bars_and_markers/bar_label_demo.html
    """

    # Debugging
    print(f"bar() :: data={data}")
    print(f"bar() :: category_labels={category_labels}")
    print(f"bar() :: bar_background_color={bar_background_color}")
    print(f"bar() :: bar_text_color={bar_text_color}")

    # Use agg
    matplotlib.use('Agg')

    # Draw bar
    fig, ax = plt.subplots(figsize=figsize)
    if direction == "vertical":
        bars = ax.bar(category_labels, data, color=bar_background_color)
    else:
        bars = ax.barh(category_labels, data, color=bar_background_color)

    # Add labels to bar
    ax.bar_label(bars, label_type='center', color=bar_text_color)

    # X and Y labels color + rotation
    plt.setp(ax.get_xticklabels(), fontsize=10, rotation=x_labels_rotation, color=category_labels_color)
    plt.setp(ax.get_yticklabels(), fontsize=10, color=category_labels_color)

    # 设置坐标轴边框样式：隐藏顶部、右侧，设置底部、左侧为灰色
    ax.spines['top'].set_visible(False)
    ax.spines['right'].set_visible(False)
    ax.spines['bottom'].set_color(category_labels_color)
    ax.spines['left'].set_color(category_labels_color)

    # Set grid color
    plt.rcParams.update({"axes.grid": False, "grid.color": "#cccccc"})

    # Save figure
    plt.savefig(f"{file_path}/{file_name}", bbox_inches='tight', dpi=200)
    fig.clear()


if __name__ == '__main__':
    category_labels = ['Dec 2022', 'Jan 2023', 'Feb 2023']
    data = [34, 58, 7]
    bar_background_color= "#4f0176"
    bar_text_color = "white"
    category_labels_color = "grey"

    bar(category_labels=category_labels,
        data=data,
        bar_background_color=bar_background_color,
        bar_text_color=bar_text_color,
        category_labels_color=category_labels_color,
        file_path=f".",
        file_name="bar.png")

关键代码解释 #

Matplotlib中坐标轴边框由spines对象管理，每个方向（top/right/bottom/left）对应独立的边框实例：

• ax.spines['top'].set_visible(False)：隐藏顶部坐标轴边框
• ax.spines['right'].set_visible(False)：隐藏右侧坐标轴边框
• ax.spines['bottom'].set_color(category_labels_color)：将底部边框颜色设为与刻度标签一致的灰色
• ax.spines['left'].set_color(category_labels_color)：将左侧边框颜色设为与刻度标签一致的灰色

将这段代码放在刻度标签设置之后、图片保存之前，即可实现目标效果。

内容的提问来源于stack exchange，提问作者Europa