Matplotlib如何调整点位置

Question

I have a horizontal barplot with a 2nd axis that has a line plot. The dots of the lineplot is not centered with the bars as you can see below.

I tried to adjust the y value of the dots [v-0.5 for v in axes.get_yticks()] which dose not affect the position. I don't know why that is.

Here is the snippet:

from random import randint
import numpy as np
import matplotlib.pyplot as plt
from typing import List, Dict
import seaborn as sns

def draw_barh_charts(
    y_vals,
    colors,
    brands,
    highlight_pos,
    lines_y,
    show_y_value=True,
    rotation=0
):
#     sns.set_style("whitegrid", {"axes.grid": False, "font.sans-serif": [cur_font]})
    y_pos = np.arange(0,len(brands))
    fig, axes = plt.subplots(figsize=(4, 8), dpi=100, sharey=True)
    patches = []
    for i, v in enumerate(y_vals):
        bars = axes.barh(y_pos[i], v)
        for j in range(len(bars)):
            bars[j].set_color(colors[1] if i==highlight_pos else colors[0])

    axes.set_yticks(y_pos)
    axes.set_yticklabels(
        brands, fontsize=16, rotation=rotation
    )
    axes.get_xaxis().set_visible(show_y_value)

    ax = axes.twinx()
    plt.plot(lines_y,
             [v-0.5 for v in axes.get_yticks()], # adjusting here doesn't work
             color='yellow',
             marker='o'
            ) 
    ax.yaxis.set_tick_params(labelsize=16)
    ax.axes.get_yaxis().set_visible(show_y_value)

    sns.despine()
    plt.show()


m = [10]*10
n = [randint(0,10) for x in range(10)]
colors = ['#C0C0C0','#62B2DA']

draw_barh_charts(m,
                 colors,
                 ['A']*10,
                 0,
                 n,
                 rotation = 0,
                 show_y_value=False)

Answer 1

What you need is the following:

• Use the correct range of y-values for plotting the line, which is [0, 1, 2, ...., 9] , ie, y_pos
• Align the y-limits of the right hand y-axis to be the same as that of the left hand y-axis

---

def draw_barh_charts(y_vals, colors, brands, highlight_pos, lines_y, show_y_value=True, rotation=0):
    y_pos = np.arange(0,len(brands))
    fig, axes = plt.subplots(figsize=(4, 8), dpi=100, sharey=True)
    patches = []
    for i, v in enumerate(y_vals):
        bars = axes.barh(y_pos[i], v)
        for j in range(len(bars)):
            bars[j].set_color(colors[1] if i==highlight_pos else colors[0])
    axes.set_yticks(y_pos)
    axes.set_yticklabels(brands, fontsize=16, rotation=rotation)
    axes.get_xaxis().set_visible(show_y_value)
    ax = axes.twinx()
    plt.plot(lines_y, y_pos,               # <--- Use correct y-values
             color='yellow', marker='o') 
    ax.yaxis.set_tick_params(labelsize=16)
    ax.axes.get_yaxis().set_visible(show_y_value)
    ax.set_ylim(axes.get_ylim())           # <--- Align both y-axes
    sns.despine()
    plt.show()

If you use show_y_value=True , this is how the plot will then look like