鼠标悬停在数据上时如何显示数据标签

Question

我正在绘制一些看起来像的数据

931,Oxfordshire,9314125,123255,Larkmead School,Abingdon,125,124,20,SUPP,8
931,Oxfordshire,9314126,123256,John Mason School,Abingdon,164,164,25,6,16
931,Oxfordshire,9314127,123257,Fitzharrys School,Abingdon,150,149,9,0,11
931,Oxfordshire,9316076,123298,Our Lady's Abingdon,Abingdon,57,57,SUPP,SUPP,16

我的基本步骤是

df = pandas.read_csv("file.csv", names=['A','B','C','D','E','F','G', 'H','I','J', 'K'], header=None)
df.replace('SUPP', 3.0, inplace=True)
df = df.convert_objects(convert_numeric=True)
df['KG'] = df['K']*1.0/df['G']
plt.plot(result['KG'])
plt.show()

但是，当我将鼠标悬停在图表上时，我真的很想获得每所学校的名称，以便探索数据。有没有办法做到这一点？

Answer 1

只是为了插入我自己的项目，看看mpldatacursor：https://github.com/joferkington/mpldatacursor

作为一个基本示例，只需调用 datacursor(hover=True, point_labels=df['E']) 即可让您获得 90% 的目标。例如，以上面的代码 sn-p 为例：

from StringIO import StringIO
import pandas as pd
import matplotlib.pyplot as plt
from mpldatacursor import datacursor

f = StringIO(
"""931,Oxfordshire,9314125,123255,Larkmead School,Abingdon,125,124,20,SUPP,8
931,Oxfordshire,9314126,123256,John Mason School,Abingdon,164,164,25,6,16
931,Oxfordshire,9314127,123257,Fitzharrys School,Abingdon,150,149,9,0,11
931,Oxfordshire,9316076,123298,Our Lady's Abingdon,Abingdon,57,57,SUPP,SUPP,16
""")
df = pd.read_csv(f, names=['A','B','C','D','E','F','G', 'H','I','J', 'K'],
                 header=None)
df.replace('SUPP', 3.0, inplace=True)
df = df.convert_objects(convert_numeric=True)
df['KG'] = df['K']*1.0/df['G']
plt.plot(df['KG'], marker='o')

datacursor(hover=True, point_labels=df['E'])

plt.show()

只要将鼠标悬停在上面，我们就会弹出一个标签。

但是，根据设计，默认行为是在行悬停/单击时显示弹出窗口。因此，当使用point_labels 选项时，结果可能与您想象的不太一样：

如果您只希望在将鼠标悬停在顶点时显示弹出窗口，您可以使用类似于此的解决方法：（在下一个版本中将有一个仅在顶点显示弹出窗口的选项，因此将来不需要此解决方法。）

from StringIO import StringIO
import pandas as pd
import matplotlib.pyplot as plt
from mpldatacursor import datacursor

f = StringIO(
"""931,Oxfordshire,9314125,123255,Larkmead School,Abingdon,125,124,20,SUPP,8
931,Oxfordshire,9314126,123256,John Mason School,Abingdon,164,164,25,6,16
931,Oxfordshire,9314127,123257,Fitzharrys School,Abingdon,150,149,9,0,11
931,Oxfordshire,9316076,123298,Our Lady's Abingdon,Abingdon,57,57,SUPP,SUPP,16
""")
df = pd.read_csv(f, names=['A','B','C','D','E','F','G', 'H','I','J', 'K'],
                 header=None)
df.replace('SUPP', 3.0, inplace=True)
df = df.convert_objects(convert_numeric=True)
df['KG'] = df['K']*1.0/df['G']
plt.plot(df['KG'], marker='o')

l, = plt.plot(df['KG'], marker='o', linestyle='', visible=False)
datacursor(l, hover=True, point_labels=df['E'])

plt.show()

此外，您可能只想显示相关学校，而不是 x、y 坐标等。要更改此设置，请使用自定义 formatter 函数：

datacursor(l, hover=True, point_labels=df['E'],
           formatter=lambda **kwargs: kwargs['point_label'][0])

最后，您可能想要一个带有更漂亮箭头和不同相对位置的白框：

datacursor(l, hover=True, point_labels=df['E'], bbox=dict(fc='white'),
           formatter=lambda **kwargs: kwargs['point_label'][0], xytext=(0, 25),
           arrowprops=dict(arrowstyle='simple', fc='white', alpha=0.5))

只是为了最后一个示例将它们组合成一个可运行的版本：

from StringIO import StringIO
import pandas as pd
import matplotlib.pyplot as plt
from mpldatacursor import datacursor

f = StringIO(
"""931,Oxfordshire,9314125,123255,Larkmead School,Abingdon,125,124,20,SUPP,8
931,Oxfordshire,9314126,123256,John Mason School,Abingdon,164,164,25,6,16
931,Oxfordshire,9314127,123257,Fitzharrys School,Abingdon,150,149,9,0,11
931,Oxfordshire,9316076,123298,Our Lady's Abingdon,Abingdon,57,57,SUPP,SUPP,16
""")
df = pd.read_csv(f, names=['A','B','C','D','E','F','G', 'H','I','J', 'K'],
                 header=None)
df.replace('SUPP', 3.0, inplace=True)
df = df.convert_objects(convert_numeric=True)
df['KG'] = df['K']*1.0/df['G']
plt.plot(df['KG'], marker='o')

l, = plt.plot(df['KG'], marker='o', linestyle='', visible=False)
datacursor(l, hover=True, point_labels=df['E'], bbox=dict(fc='white'),
           formatter=lambda **kwargs: kwargs['point_label'][0], xytext=(0, 25))

plt.show()