散景 HoverTool 显示“???”

Question

我正在使用 Python 进入 Bokeh 库，但遇到了一些麻烦。我有来自 Bokeh 教程网站的以下代码：

from bokeh.plotting import figure 
from bokeh.io import output_notebook, show
output_notebook()
from bokeh.sampledata.autompg import autompg
from bokeh.models import HoverTool
from bokeh.plotting import ColumnDataSource

grouped = autompg.groupby("yr")
mpg2 = grouped["mpg"]
avg = mpg2.mean()
std = mpg2.std()
years = list(grouped.groups.keys())
american = autompg[autompg["origin"]==1]
japanese = autompg[autompg["origin"]==3]

p = figure(title="MPG by Year (Japan and US)")

p.vbar(x=years, bottom=avg-std, top=avg+std, width=0.8, 
       fill_alpha=0.2, line_color=None, legend="MPG 1 stddev")

p.circle(x=japanese["yr"], y=japanese["mpg"], size=10, alpha=0.5,
         color="red", legend="Japanese")

p.triangle(x=american["yr"], y=american["mpg"], size=10, alpha=0.3,
           color="blue", legend="American")

p.legend.location = "top_left"
show(p)

它有效，但我想添加一个功能，当您将鼠标悬停在一个点上时，它会显示马力。我试过的是

grouped = autompg.groupby("yr")
mpg = grouped["mpg"]
avg = mpg.mean()
std = mpg.std()
years = list(grouped.groups.keys())
american = autompg[autompg["origin"]==1]
japanese = autompg[autompg["origin"]==3]

source = ColumnDataSource(data=
   dict(autompg)
)

hover1 = HoverTool(tooltips=[("hp", "@hp")])


p = figure(title="MPG by Year (Japan and US)",tools=[hover1])

p.vbar(x=years, bottom=avg-std, top=avg+std, width=0.8, 
       fill_alpha=0.2, line_color=None, legend="MPG 1 stddev")

p.circle(x=japanese["yr"], y=japanese["mpg"], size=10, alpha=0.5,
         color="red", legend="Japanese")

p.triangle(x=american["yr"], y=american["mpg"], size=10, alpha=0.3,
           color="blue", legend="American")

p.legend.location = "top_left"
show(p)

所以定义一个我希望能做到这一点的 HoverTool。不幸的是，它只显示“hp: ???” 对于每个条目。我认为是数据源的问题，但我在这里没有太多经验，自己也无法弄清楚。我试过没有 dict() 的源代码，我试过将它设置为美国或日本，但这没有任何区别。

谢谢！

Answer 1

您需要将 传递source给字形函数，并引用坐标的列名。如果您将文字列表/数组（如您在上面所做的那样）传递给circle等，那么 Bokeh 将在幕后为该数据创建一个 CDS，但仅使用您传递给字形函数的数据（即没有额外的列，例如“生命值”）。由于您试图为不同的数据子集绘制不同的字形，最简单的方法是使用 aCDSView在客户端对它们进行分组。像这样的东西：

from bokeh.plotting import figure
from bokeh.io import show
from bokeh.sampledata.autompg import autompg
from bokeh.models import ColumnDataSource, CDSView, GroupFilter, HoverTool

p = figure()

# Bokeh factors must be strings
autompg.origin = [str(x) for x in autompg.origin]

source = ColumnDataSource(autompg)

# view for just japanese origin
japanese = CDSView(source=source, filters=[GroupFilter(column_name='origin', group="1")])

# draw circles for just the japanese view
p.circle(x="yr", y="mpg", size=10, alpha=0.5, color="red", legend="Japanese",
         source=source, view=japanese)

# view for just japanese origin
american = CDSView(source=source, filters=[GroupFilter(column_name='origin', group="3")])

# draw triangles for just the american view
p.triangle(x="yr", y="mpg", size=10, alpha=0.5, color="blue", legend="american",
         source=source, view=american)

p.add_tools(HoverTool(tooltips=[("hp", "@hp")]))

show(p)