How to add labels to dots in bokeh?

Question

So what I'd like to do is a simple figure with lines and circles like http://docs.bokeh.org/en/latest/docs/quickstart.html#getting-started but with labels which show after mouseover over the circles.

Would that be possible?

Answer 1

From what I understand HoverTool is what you are looking for. You can see an example of it being used on rect glyphs instead of circles (and lines) but that should be the final result.

Here's a modified version of the line example with circle glyphs and a hover tool:

from collections import OrderedDict
import numpy as np

from bokeh.plotting import *
from bokeh.models import HoverTool

x = np.linspace(0, 4*np.pi, 200)
y = np.sin(x)

output_file("line_dots.html", title="line.py example")

source = ColumnDataSource(
    data=dict(
        x=x,
        y=y,
        label=["%s X %s" % (x_, y_) for x_, y_ in zip(x, y)]
    )
)
TOOLS="crosshair,pan,wheel_zoom,box_zoom,reset,hover,previewsave"
p = figure(title="simple line example", tools=TOOLS)
p.line('x', 'y', color="#2222aa", line_width=2, source=source)
p.circle('x', 'y', color="#2222aa", line_width=2, source=source)

hover =p.select(dict(type=HoverTool))
hover.tooltips = OrderedDict([
    ("index", "$index"),
    ("(xx,yy)", "(@x, @y)"),
    ("label", "@label"),
])

show(p)