Plotly 简明教程

Plotly - Legends

默认情况下，具有多个迹线的 Plotly 图表会自动显示图例。如果它只有一个迹线，则不会自动显示。若要显示，请将 Layout 对象的 showlegend 参数设置为 True。

By default, Plotly chart with multiple traces shows legends automatically. If it has only one trace, it is not displayed automatically. To display, set showlegend parameter of Layout object to True.

layout = go.Layoyt(showlegend = True)

图例的默认标签是迹线对象名称。若要显式设置图例标签，请设置迹线的名称属性。

Default labels of legends are trace object names. To set legend label explicitly set name property of trace.

在以下示例中，绘制了两个带有名称属性的散点迹线。

In following example, two scatter traces with name property are plotted.

import numpy as np
import math #needed for definition of pi

xpoints = np.arange(0, math.pi*2, 0.05)
y1 = np.sin(xpoints)
y2 = np.cos(xpoints)
trace0 = go.Scatter(
   x = xpoints,
   y = y1,
   name='Sine'
)
trace1 = go.Scatter(
   x = xpoints,
   y = y2,
   name = 'cos'
)
data = [trace0, trace1]
layout = go.Layout(title = "Sine and cos", xaxis = {'title':'angle'}, yaxis = {'title':'value'})
fig = go.Figure(data = data, layout = layout)
iplot(fig)

该图外观如下 −

The plot appears as below −

legends trace object