色标反方向

Question

如何在绘图中反转色标的方向？我正在尝试将色标Viridis用于标记图

import plotly.graph_objs as go
import plotly.plotly as py

import numpy as np

trace1 = go.Scatter(
    y = np.random.randn(500),
    mode='markers',
    marker=dict(
        size=16,
        color = np.random.randn(500), #set color equal to a variable
        colorscale='Viridis',
        showscale=True
    )
)
data = [trace1]

py.iplot(data, filename='scatter-plot-with-colorscale')

但是我希望对于更高的值它会更暗，对于更低的值它会更亮。有什么方法可以执行此操作而无需定义我自己的自定义色标或更改我的颜色参数数组？

Answer 1

只需将其添加reversescale = True到绘图定义中，色标就会反转。

import plotly
plotly.offline.init_notebook_mode()
trace = plotly.graph_objs.Heatmap(z=[[1, 20, 30],
                                     [20, 1, 60],
                                     [30, 60, 1]],
                                  reversescale=True)

plotly.offline.iplot([trace])