matplotlib 3.4.0新增功能

现在有一个内置的Axes。Bar_label helper方法来自动标记条形图:

fig, ax = plt.subplots()
bars = ax.barh(indexes, values)

ax.bar_label(bars)

注意，对于分组/堆叠的条形图，会有多个条形容器，它们都可以通过ax.containers访问:

for bars in ax.containers:
    ax.bar_label(bars)

更多的细节:

如何添加成千上万的分隔符(逗号)标签 如何应用f字符串标签 如何添加标签间距

更新:现在有一个内置的方法!向下滚动“matplotlib 3.4.0中的新功能”的几个答案。

如果你不能升级到那么远，也不需要太多代码。添加:

for i, v in enumerate(y):
    ax.text(v + 3, i + .25, str(v), color='blue', fontweight='bold')

结果:

y值v是ax的x位置值和字符串值。文本，很方便的是，每个柱形图都有一个度量值1，所以枚举I是y位置。

我注意到api示例代码包含一个条形图的示例，每个条形图上显示的是条形图的值:

"""
========
Barchart
========

A bar plot with errorbars and height labels on individual bars
"""
import numpy as np
import matplotlib.pyplot as plt

N = 5
men_means = (20, 35, 30, 35, 27)
men_std = (2, 3, 4, 1, 2)

ind = np.arange(N)  # the x locations for the groups
width = 0.35       # the width of the bars

fig, ax = plt.subplots()
rects1 = ax.bar(ind, men_means, width, color='r', yerr=men_std)

women_means = (25, 32, 34, 20, 25)
women_std = (3, 5, 2, 3, 3)
rects2 = ax.bar(ind + width, women_means, width, color='y', yerr=women_std)

# add some text for labels, title and axes ticks
ax.set_ylabel('Scores')
ax.set_title('Scores by group and gender')
ax.set_xticks(ind + width / 2)
ax.set_xticklabels(('G1', 'G2', 'G3', 'G4', 'G5'))

ax.legend((rects1[0], rects2[0]), ('Men', 'Women'))


def autolabel(rects):
    """
    Attach a text label above each bar displaying its height
    """
    for rect in rects:
        height = rect.get_height()
        ax.text(rect.get_x() + rect.get_width()/2., 1.05*height,
                '%d' % int(height),
                ha='center', va='bottom')

autolabel(rects1)
autolabel(rects2)

plt.show()

输出:

供参考matplotlib的“barh”中高度变量的单位是什么?(到目前为止，还没有简单的方法为每个条设置固定的高度)

简单地加上这个:

for i in range(len(y)):
    plt.text(x= y[i],y= i,s= y[i], c='b')

对于列表(y)中的每一项，将值打印为指定位置(x= x轴上的位置和y= y轴上的位置)的绘图上的蓝色文本

我知道这是一个老帖子，但我通过谷歌登陆了几次，认为没有给出的答案是真正令人满意的。尝试使用以下函数之一:

编辑:因为我在这个旧线程上得到了一些喜欢，我想分享一个更新的解决方案(基本上把我之前的两个函数放在一起，并自动决定它是一个bar还是hbar plot):

def label_bars(ax, bars, text_format, **kwargs):
    """
    Attaches a label on every bar of a regular or horizontal bar chart
    """
    ys = [bar.get_y() for bar in bars]
    y_is_constant = all(y == ys[0] for y in ys)  # -> regular bar chart, since all all bars start on the same y level (0)

    if y_is_constant:
        _label_bar(ax, bars, text_format, **kwargs)
    else:
        _label_barh(ax, bars, text_format, **kwargs)


def _label_bar(ax, bars, text_format, **kwargs):
    """
    Attach a text label to each bar displaying its y value
    """
    max_y_value = ax.get_ylim()[1]
    inside_distance = max_y_value * 0.05
    outside_distance = max_y_value * 0.01

    for bar in bars:
        text = text_format.format(bar.get_height())
        text_x = bar.get_x() + bar.get_width() / 2

        is_inside = bar.get_height() >= max_y_value * 0.15
        if is_inside:
            color = "white"
            text_y = bar.get_height() - inside_distance
        else:
            color = "black"
            text_y = bar.get_height() + outside_distance

        ax.text(text_x, text_y, text, ha='center', va='bottom', color=color, **kwargs)


def _label_barh(ax, bars, text_format, **kwargs):
    """
    Attach a text label to each bar displaying its y value
    Note: label always outside. otherwise it's too hard to control as numbers can be very long
    """
    max_x_value = ax.get_xlim()[1]
    distance = max_x_value * 0.0025

    for bar in bars:
        text = text_format.format(bar.get_width())

        text_x = bar.get_width() + distance
        text_y = bar.get_y() + bar.get_height() / 2

        ax.text(text_x, text_y, text, va='center', **kwargs)

现在你可以将它们用于常规条形图:

fig, ax = plt.subplots((5, 5))
bars = ax.bar(x_pos, values, width=0.5, align="center")
value_format = "{:.1%}"  # displaying values as percentage with one fractional digit
label_bars(ax, bars, value_format)

或者对于水平条形图:

fig, ax = plt.subplots((5, 5))
horizontal_bars = ax.barh(y_pos, values, width=0.5, align="center")
value_format = "{:.1%}"  # displaying values as percentage with one fractional digit
label_bars(ax, horizontal_bars, value_format)

对于熊猫人来说:

ax = s.plot(kind='barh') # s is a Series (float) in [0,1]
[ax.text(v, i, '{:.2f}%'.format(100*v)) for i, v in enumerate(s)];

就是这样。 或者，对于那些更喜欢使用apply而不是enumerate循环的人:

it = iter(range(len(s)))
s.apply(lambda x: ax.text(x, next(it),'{:.2f}%'.format(100*x)));

同时,斧头。Patches将为您提供与ax.bar(…)相同的条形图。如果你想应用@SaturnFromTitan的功能或其他人的技术。