Python pandas / matplotlib 在条形图列上方注释标签
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Python pandas / matplotlib annotating labels above bar chart columns
提问by ccsv
How do I add the label for the value to display above the bars in the bargraph here:
如何添加值的标签以显示在条形图中的条形上方：
import pandas as pd
import matplotlib.pyplot as plt
df=pd.DataFrame({'Users': [ 'Bob', 'Jim', 'Ted', 'Jesus', 'James'],
'Score': [10,2,5,6,7],})
df = df.set_index('Users')
df.plot(kind='bar', title='Scores')
plt.show()
回答by Kamil Sindi
A solution without accessing the DataFrame is to use the patches attribute:
不访问 DataFrame 的解决方案是使用 patch 属性：
ax = df.plot.bar(title="Scores")
for p in ax.patches:
ax.annotate(str(p.get_height()), xy=(p.get_x(), p.get_height()))
Note you have to play around with the xy kwarg (2nd arg) to get the label position you desire.
请注意，您必须使用 xy kwarg（第二个参数）来获得所需的标签位置。
Vertical Bars
竖条
I found this formatting to be the best in general:
我发现这种格式通常是最好的：
ax.annotate("%.2f" % p.get_height(), (p.get_x() + p.get_width() / 2., p.get_height()), ha='center', va='center', xytext=(0, 10), textcoords='offset points')
Horizontal Bars
单杠
I found the following format to work well with horizontal bars:
我发现以下格式适用于水平条：
ax.annotate("%.2f" % p.get_width(), (p.get_x() + p.get_width(), p.get_y()), xytext=(5, 10), textcoords='offset points')
回答by joemar.ct
Capture the axis where the plot is drawn into, then manipulate it as a usual matplotlibobject. Putting the value above the bar will be something like this:
捕获绘图所在的轴，然后将其作为通常的matplotlib对象进行操作。将值放在栏上方将是这样的：
ax = df.plot(kind='bar', title='Scores')
ax.set_ylim(0, 12)
for i, label in enumerate(list(df.index)):
score = df.ix[label]['Score']
ax.annotate(str(score), (i, score + 0.2))
