如何使用 matplotlib 获得 plot 的步进单元？

Question

 ax.text(x=v+ ?? , y= i+addition, s= str(v), color='black')

I created various plots of type horizontal bar chart, and now I want to add text next to each bar in each plot.At the?? I want to add quarter of the step unit of each plot, where I am adding the text. So for example if the step unit is 80, then it should be 20. ?? is the horizontal distance between the bar and the text. it can't be constant, because I am basically creating many plots with different scales. Any suggestions??

My question is basically if there is a method with which i can just get the step unit of a plot, similar getting the xlim and ylim? I am assuming the step unit is automatically calculated by default.

Easy clarification of the question

Answer 1

You probably want to use ax.annotate ( doc ) that lets you specify the offset of the text from a point in data space in screen space . For example:

import matplotlib.pyplot as plt
import numpy as np

fig, (ax1, ax2) = plt.subplots(2, constrained_layout=True)

vals = np.arange(5) + 1


def bar_and_label(ax, y, width, text):
    ax.barh(y, width)
    ax.annotate(
        text=text,
        xy=(width[0], 0),
        xytext=(5, 0),
        textcoords="offset points",
        va="center",
        ha="left",
    )


bar_and_label(ax1, range(len(vals)), vals, "a")
bar_and_label(ax2, range(len(vals)), vals * 100, "b")

This makes sure that the space between the bar and the label is always the same no matter what scale the data is on!

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You may also be interested in the new in mpl3.4 feature ax.bar_label ( doc ) method.