在散景中修改悬停时的显示格式

Question

I have datetime on x-axis and I was trying to plot it as a datetime, but apparently, according to this Bokeh can only have number axes. Unless that's changed by now, then please let me know. But I was wondering if there's maybe at least a way to display datetime on hover rather than timestamp (something like 153286000 )?

p.select_one(HoverTool).tooltips = [('Datetime', '@x'),('Position', '@y')]

I tried adding .to_datetime() but that didn't work.

Answer 1

You need to set the x_axis_type = "datetime" and use formatters for the datetime like this:

p.select_one(HoverTool).formatters = {'Datetime': 'datetime'}

See full example below (Bokeh v1.1.0). See also Bokeh documentation on tooltips formatting.

import numpy as np
from bokeh.io import output_file, show
from bokeh.models import ColumnDataSource, HoverTool
from bokeh.plotting import figure
from bokeh.sampledata.stocks import AAPL

def datetime(x):
    return np.array(x, dtype = np.datetime64)

source = ColumnDataSource(data = {'date'      : datetime(AAPL['date'][::10]),
                                  'adj close' : AAPL['adj_close'][::10],
                                  'volume'    : AAPL['volume'][::10]})

p = figure(plot_height = 250, x_axis_type = "datetime", sizing_mode = "scale_width")

p.background_fill_color = "#f5f5f5"
p.grid.grid_line_color = "white"
p.xaxis.axis_label = 'Date'
p.yaxis.axis_label = 'Price'
p.axis.axis_line_color = None

p.line(x = 'date', y = 'adj close', line_width = 2, color = '#ebbd5b', source = source)

hover = HoverTool(mode = 'vline')
hover.tooltips = [('date', '@date{%F}'), ('close', '$@{adj close}{%0.2f}'), ('volume', '@volume{0.00 a}')]
hover.formatters = {'date': 'datetime', 'adj close' : 'printf'}
p.add_tools(hover)

show(p)

Result: