Bokeh：使用MultiLine字形时无法生成不同的线条颜色

Question

我已经使用Bokeh生成了多折线图，并使用滑块对其进行了更新。我找不到一种方法来用不同的颜色绘制每条线。我尝试使用itertools遍历调色板，并传递一系列调色板颜色。

这是itertools方法（full_source支持使用CustomJS的滑块交互）：

import itertools
from bokeh.plotting import figure
from bokeh.embed import components
from bokeh.models import CustomJS, ColumnDataSource, Slider
from bokeh.palettes import Category20 as palette
from bokeh.models.glyphs import MultiLine
from bokeh.models.widgets import DataTable, TableColumn
from bokeh.layouts import column, row
from bokeh.io import show

data={'xdata':[[0, 1, 2, 4, 5, 6, 10, 11, 12], [4, 8, 16, 0, 13, 21, -3, 9, 21]],
      'ydata':[[4, 8, 16, 0, 13, 21, -3, 9, 21], [0, 1, 2, 4, 5, 6, 10, 11, 12]]}
colors=itertools.cycle(palette[2])

source = ColumnDataSource(data)
full_source = ColumnDataSource(data)
glyph = MultiLine(xs='xdata', ys='ydata', line_color = next(colors))

p = figure(title = None, plot_width = 400, plot_height = 400, toolbar_location = None)
p.add_glyph(source, glyph)
print(glyph.line_color)
show(p)

这给出了两条线，但是颜色相同。 print(glyph.line_color)仅显示通过的一种颜色-＃1f77b4（这是Category20调色板中的第一种颜色）

我也尝试使用发现的示例here：

import itertools
from bokeh.plotting import figure
from bokeh.embed import components
from bokeh.models import CustomJS, ColumnDataSource, Slider
from bokeh.palettes import Spectral11
from bokeh.models.glyphs import MultiLine
from bokeh.models.widgets import DataTable, TableColumn
from bokeh.layouts import column, row
from bokeh.io import show

data={'xdata':[[0, 1, 2, 4, 5, 6, 10, 11, 12], [4, 8, 16, 0, 13, 21, -3, 9, 21]],
      'ydata':[[4, 8, 16, 0, 13, 21, -3, 9, 21], [0, 1, 2, 4, 5, 6, 10, 11, 12]]}
my_pallet = Spectral11[0:2]

source = ColumnDataSource(data)
full_source = ColumnDataSource(data)
glyph = MultiLine(xs='xdata', ys='ydata', line_color = my_pallet)

p = figure(title = None, plot_width = 400, plot_height = 400, toolbar_location = None)
p.add_glyph(source, glyph)
print(glyph.line_color)
show(p)

这给出了：ValueError expected an element of either String, Dict(Enum('expr', 'field', 'value', 'transform'), Either(String, Instance(Transform), Instance(Expression), Color)) or Color, got ['#5e4fa2', '#3288bd', '#66c2a5']

如何将调色板中的多种颜色转换成多线图？

Answer 1

好吧，好像我没有正确使用ColumnDataSource。通过将颜色作为数据Dict中的另一个key：value对传递到ColumnDataSource中，它可以工作。我也可以摆脱MultiLine字形对象。

工作代码为：

from bokeh.plotting import figure
from bokeh.embed import components
from bokeh.models import CustomJS, ColumnDataSource, Slider
from bokeh.palettes import Category20 as palette
from bokeh.models.widgets import DataTable, TableColumn
from bokeh.layouts import column, row
from bokeh.io import show

data = {'xs':[[...,...,..,][...,...,...]],'ys':[[...,...,..,][...,...,...]]}
length = len(data)
colors = palette[length]

#because Category20 has a minimum of 3 values, and length may be smaller
while len(colors)>length:
    colors.pop()

data['color'] = colors
source = ColumnDataSource(data)
full_source = ColumnDataSource(data)

p = figure(title = None, plot_width = 400, plot_height = 400, toolbar_location = None)
p.multi_line(xs='xdata', ys='ydata', source=source, line_color='color')