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How do I change the date/time format displayed in the Bokeh hovertool?

Currently the Bokeh hovertool spits out my date values as a 13-digit number. How do I change the format of how it's displayed?
Below is my code...also I've specified which line of code the date/time is in.
from bokeh.plotting import figure, show
from bokeh.models import ColumnDataSource, HoverTool
from bokeh.io import output_notebook
x = dff.P2_VWC
y = dff.P2_EC
bok = figure(title="Simple line example", x_axis_label='x', y_axis_label='y')
bok.line(x, y, legend_label="Hysteresis", line_width=2)
show(bok)
output_notebook()
#Specify the selection tools to be made available
select_tools = ['box_select', 'lasso_select', 'poly_select', 'tap', 'reset']
# Format the tooltip
tooltips = [
('VWC', '#P2_VWC'),
('EC', '#P2_EC'),
('Date', '#date_time') # !THIS DATE NEEDS FORMATTED!
]
p = figure(plot_width=800, plot_height=400, x_axis_type='linear', title = "VWC v. Bulk EC")
p.line(x="P2_VWC", y="P2_EC", source=dff)
p.xaxis.axis_label = 'VWC'
p.yaxis.axis_label = 'Bulk EC'
p.add_tools(HoverTool(tooltips=tooltips))
show(p)
Thank you for your time!

Only a few lines of code needed to be changed but they are below. {%F %T} can be added to the date/time code to specify what you want.
from bokeh.plotting import figure, show
from bokeh.models import ColumnDataSource, HoverTool
from bokeh.io import output_notebook
output_notebook()
#Specify the selection tools to be made available
select_tools = ['box_select', 'lasso_select', 'poly_select', 'tap', 'reset']
# Format the tooltip
# https://docs.bokeh.org/en/latest/docs/reference/models/formatters.html#bokeh.models.formatters.DatetimeTickFormatter
tooltips = [
('VWC', '#P2_VWC'),
('EC', '#P2_EC'),
('Date', '#date_time{%F %T}'),
]
p = figure(plot_width=800, plot_height=800, x_axis_type='linear', title = "VWC v. Bulk EC")
p.line(x="P2_VWC", y="P2_EC", source=df1)
p.xaxis.axis_label = 'VWC'
p.yaxis.axis_label = 'Bulk EC'
p.add_tools(HoverTool(tooltips=tooltips, formatters={'#date_time': 'datetime'}))
show(p)

Python: how to update bokeh patches field?

I am working with bokeh and I would like to update the field value of a patch.
First I conver a geodataframe gdf into a GeoJSONDataSource
from bokeh.models import LogColorMapper
from bokeh.palettes import Viridis256 as palette
from bokeh.models.glyphs import Patch
from bokeh.models import GeoJSONDataSource, Select
geo_gdf = GeoJSONDataSource(geojson=gdf.to_json())
w = 200
h = 200
field = 'col1' ## choose col1 as field to plot
vmin = min(gdf[field])
vmax = max(gdf[field])
## create plot
p = figure(plot_width=w,plot_height=h)
color_mapper = LogColorMapper(palette=palette, low=vmin, high=vmax)
## Patches definition
grid=p.patches('xs', 'ys', source = geo_source2, name="grid",
fill_color={'field': field, 'transform': color_mapper},
fill_alpha=0.5, line_color="gray", line_width=2)
I would like to change the field by selecting an option
select = Select(title="Options", options = ['Col1', 'Col2'], value = 'Col1')
def update_plot(attrname, old, new):
option = select.value
if option == 'Col1':
p.field = 'Col1'
if option == 'Col2':
p.field = 'Col2'
select.on_change('value', update_plot)
curdoc().add_root(select)

field is not a property of the glyph, it is a specification for how a particular property (e.g. fill_color) should be handled. You will need to update it the same way you set it:
grid.glyph.fill_color = {'field': option, 'transform': color_mapper}

bokeh hover multiline with datetime axis

I want to create a multiline Bokeh plot with datetime axis and a hover tool that shows the datetime of the data point. This should be supported and I have tried to obtain the intended behaviour in two ways:
Use hover.formatters to format the x-value. This has no effect on the plot.
Add a description variable with the correctly formatted date/time values. This results in a hover tool where all date/time values are displayed in a list for each point.
I have included a smaller example of my code that illustrates my approach and the result. It is used in conjunction with a checkboxgroup that updates the data. This is why a new ColumnDataSource is made from the dataframe.
import pandas as pd
import numpy as np
from bokeh.io import output_file, show
from bokeh.plotting import figure
from bokeh.models import HoverTool, ColumnDataSource
from bokeh.palettes import Spectral4
from bokeh.layouts import column
#output_file("demo.html")
available_quant = ["LACTIC_ACID", "GLUCOSE", "XYLOSE", "FORMIC_ACID"]
quant_legend = ["Lactic acid", "Glucose", "Xylose", "Formic acid"]
Create a dataframe with 4 quantities and the time
datelist = pd.date_range(end = pd.datetime.today(), periods=100).tolist()
desc = datelist
for i, date in enumerate(datelist):
desc[i] = str(date)
RT_x = np.linspace(-5, 5, num=100)
lactic = RT_x**2
data = {'time': datelist, 'desc': desc, 'LACTIC_ACID': RT_x**2 + 2, 'GLUCOSE': RT_x**2, 'XYLOSE': RT_x**2 - 2, 'FORMIC_ACID': RT_x**2 - 4}
df = pd.DataFrame.from_dict(data)
df['time'] = pd.to_datetime(df['time'], format = "%Y-%m-%d %H:%M:%S")
Copy the relevant data to a columndatasource
substance_colors = Spectral4
quant_to_plot = available_quant
xs = []
ys = []
xsprint = []
colors = []
labels = []
for i, substance in enumerate(quant_to_plot):
xs.append(list(df['time']))
ys.append(list(df[substance]))
xsprint.append(list(df['desc']))
index = available_quant.index(substance)
colors.append(substance_colors[index])
labels.append(quant_legend[index])
new_src = ColumnDataSource(data={'x': xs, 'y': ys, 'desc': xsprint, 'color': colors, 'label': labels})
Make the first plot using hover.formatters
p = figure(plot_width=800, plot_height=400, x_axis_type="datetime", title = 'Demo', x_axis_label = 'Time', y_axis_label = 'c [g/mL]')
p.multi_line('x','y', color = 'color', legend = 'label', source = new_src)
hover = HoverTool(tooltips=[('Type','#label'),
('Time','$x'),
('Conc','$y')],
formatters={'Time': 'datetime'},
mode = 'mouse',
line_policy='next')
p.add_tools(hover)
p.legend.location = "top_left"
p.legend.orientation = "horizontal"
Make second plot using description variable
p2 = figure(plot_width=800, plot_height=400, x_axis_type="datetime", title = 'Demo', x_axis_label = 'Time', y_axis_label = 'c [g/mL]')
p2.multi_line('x','y', color = 'color', legend = 'label', source = new_src)
hover = HoverTool(tooltips=[('Type','#label'),
('Time','#desc'),
('Conc','$y')],
mode = 'mouse',
line_policy='nearest')
p2.add_tools(hover)
mylayout = column(p, p2)
show(mylayout)
Am I missing something trivial? I am running Bokeh 0.13.0 and python 3.6.4.

The first approach works with the following modification of the hovertool:
hover = HoverTool(tooltips=[('Type','#label'),
('Time','$x{%F}'),
('Conc','$y')],
formatters={'$x': 'datetime'},
mode = 'mouse',
line_policy='nearest')

Changing colors on bokeh patches plot real time

I'm trying to create a bokeh plot of the US States, and color each of the state according to some data. Now using this tutorial I managed to create this, but I also want to enhance it, and add a slider to it, to change the values displayed. For example like displaying separate years.
With the help of this tutorial, I managed to add the slider, and the underlying data does change, according to the hover text, but the colors aren't recalculated, and so the visual representation does not match the values.
This is the code I've used, from a Jupyter notebook, so anybody who wants to try can reproduce
from bokeh.io import show, output_notebook
from bokeh.models import (
ColumnDataSource,
HoverTool,
LogColorMapper,
Range1d, CustomJS, Slider
)
from bokeh.palettes import Inferno256 as palette
from bokeh.plotting import figure
from bokeh.layouts import row, widgetbox
from bokeh.sampledata.us_counties import data as counties
from bokeh.sampledata.us_states import data as states
from bokeh.sampledata.unemployment import data as unemployment
import pandas as pd
import random
output_notebook()
palette.reverse()
states_accumulated ={}
available_state_codes = states.keys()
for key, value in counties.items():
state_name = value["state"].upper()
if state_name in states.keys() and "number" not in states[state_name]:
states[state_name]["number"] = key[0]
for key,state in states.items():
state["code"] = key
state_list = []
for key,state in states.items():
state_list.append(state)
unemployment_transf = []
for key,value in unemployment.items():
unemployment_transf.append({
"State":key[0],
"County":key[1],
"Value":value
})
unemp_df = pd.DataFrame(unemployment_transf)
unemp_sum = unemp_df.groupby("State").mean()["Value"]
unemp_sum = unemp_sum.sort_index()
unemp_sum_flat = {key:value for key, value in unemp_sum.items()}
for state in state_list:
state["value"] = unemp_sum_flat[state["number"]]
state_df = pd.DataFrame(state_list)
color_mapper = LogColorMapper(palette=palette)
state_xy = (list(state_df["lons"].values),list(state_df["lats"].values))
max_x = max([max(l) for l in state_xy[0]])
max_y = max([max(l) for l in state_xy[1]])
min_x = min([min(l) for l in state_xy[0]])
min_y = min([min(l) for l in state_xy[1]])
data=dict(
x=state_xy[0],
y=state_xy[1],
name=list(state_df["name"].values),
used = list(state_df["value"].values)
)
data['1999'] = list(state_df["value"].values)
data['2000'] = [random.randrange(0,10) for i in range(len(state_xy[0]))]
source = ColumnDataSource(data)
TOOLS = "pan,wheel_zoom,reset,hover,save"
p = figure(
title="States", tools=TOOLS,
x_axis_location=None, y_axis_location=None
)
p.width=450
p.height = 450
p.x_range= Range1d(-170,-60)
p.y_range = Range1d(min_y-10,max_y+10)
p.grid.grid_line_color = None
renderer = p.patches('x', 'y', source=source,
fill_color={'field': 'used', 'transform': color_mapper},
fill_alpha=0.7, line_color="white", line_width=0.5)
hover = p.select_one(HoverTool)
hover.point_policy = "follow_mouse"
hover.tooltips = [
("Name", "#name"),
("Unemployment rate)", "#used%"),
("(Long, Lat)", "($x, $y)"),
]
callback = CustomJS(args=dict(source=source,plot=p,color_mapper = color_mapper,renderer = renderer), code="""
var data = source.data;
var year = year.value;
used = data['used']
should_be = data[String(year)]
for (i = 0; i < should_be.length; i++) {
used[i] = should_be[i];
}
""")
year_slider = Slider(start=1999, end=2000, value=1999, step=1,
title="year", callback=callback)
callback.args["year"] = year_slider
layout = row(
p,
widgetbox(year_slider),
)
show(layout)
Sample images of the plot:
What I would like to accomplish, is that when I change the slider, the colors on the plot should change. Now I think the JS callback should call some kind of redraw or recalculate, but I haven't found any documentation about it. Is there a way to do this?

append source.change.emit() to the Javascipt code to trigger the change event.

Appending source.trigger("change"); to the CustomJS seems to solve the problem, now as the slider changes, the colors change.

Python: Bokeh hover tool tips date time [duplicate]

I am trying to get a line plot via Bokeh in Python. I am new to Bokeh and I am trying to apply hover tool tips over the plot. The x-axis of the plot has Timestamp values which are converted into epoch string. I've reviewed some same problems here and tried to use the workaround for my case but it doesn't seem to work. On the plot it gives ??? where the time should show up.
Any suggestions for my code?
Timestamp is in format 2016-12-29 02:49:12
Also can someone tell how do I format x-axis ticks to show up vertically ?
p = figure(width=1100,height=300,tools='resize,pan,wheel_zoom,box_zoom,reset,previewsave,hover',logo=None)
p.title.text = "Time Series for Price in Euros"
p.grid.grid_line_alpha = 0
p.xaxis.axis_label = "Day"
p.yaxis.axis_label = "Euros"
p.ygrid.band_fill_color = "olive"
p.ygrid.band_fill_alpha = 0.1
p.circle(df['DateTime'],df['EuP'], size=4, legend='close',
color='darkgrey', alpha=0.2)
p.xaxis.formatter = DatetimeTickFormatter(formats=dict(
hours=["%d %B %Y"],
days=["%d %B %Y"],
months=["%d %B %Y"],
years=["%d %B %Y"],
))
source = ColumnDataSource(data=dict(time=[x.strftime("%Y-%m-%d %H:%M:%S")for x in df['DateTime']]))
hover = p.select(dict(type=HoverTool))
hover.tooltips = {"time":'#time', "y":"$y"}
hover.mode = 'mouse'
p.line(df['DateTime'],df['EuP'],legend='Price',color='navy',alpha=0.7)

Since this answer was originally posted, new work has gone into Bokeh to make things simpler. A datetime field can be formatted as a datetime directly by the hover tool, by specifying a formatter, e.g.:
HoverTool(tooltips=[('date', '#DateTime{%F}')],
formatters={'#DateTime': 'datetime'})
It is no longer necessary to pre-format date fields in the data source as below. For more information see Formatting Tooltip Fields
OLD ANSWER:
The problem with your tooltip is you created a source with the string representation of the dates, but the p.line() call is unaware of it. So you have to pass in a columndatasource that has the tooltip, the x and y values.
Here is a working variant of your code:
from bokeh.plotting import figure, show
from bokeh.models.formatters import DatetimeTickFormatter
from bokeh.models import ColumnDataSource
from bokeh.models.tools import HoverTool
import pandas as pd
import numpy as np
data = {
'DateTime' : pd.Series(
['2016-12-29 02:49:12',
'2016-12-30 02:49:12',
'2016-12-31 02:49:12'],
dtype='datetime64[ns]'),
'EuP' : [20,40,15]
}
df = pd.DataFrame(data)
df['tooltip'] = [x.strftime("%Y-%m-%d %H:%M:%S") for x in df['DateTime']]
p = figure(width=1100,height=300,tools='resize,pan,wheel_zoom,box_zoom,reset,previewsave,hover',logo=None)
p.title.text = "Time Series for Price in Euros"
p.grid.grid_line_alpha = 0
p.xaxis.axis_label = "Day"
p.yaxis.axis_label = "Euros"
p.ygrid.band_fill_color = "olive"
p.ygrid.band_fill_alpha = 0.1
p.circle(df['DateTime'],df['EuP'], size=4, legend='close',
color='darkgrey', alpha=0.2)
p.xaxis.formatter = DatetimeTickFormatter(formats=dict(
hours=["%d %B %Y"],
days=["%d %B %Y"],
months=["%d %B %Y"],
years=["%d %B %Y"],
))
hover = p.select(dict(type=HoverTool))
tips = [('when','#tooltip'), ('y','$y')]
hover.tooltips = tips
hover.mode = 'mouse'
p.line(x='DateTime', y='EuP', source=ColumnDataSource(df),
legend='Price',color='navy',alpha=0.7)
show(p)
Also note there is an open issue about the lack of formatting options in the bokeh tooltip. There might be an easier way to not have to format the datestrings as a separate column:
https://github.com/bokeh/bokeh/issues/1239
Also can someone tell how do I format x-axis ticks to show up vertically ?
They look fine to me, sorry I cannot help on that one.
Hope this helps!
PS it would be better next time if you posted a working script with import statements, and a mocked up dataframe to make it possible to test. It took some time to sort it all out. But I am learning Bokeh so that is fine :)

Sorry for not commenting, I don't have enough reputation for that.
The accepted answer by #Alex doesn't work for me (Bokeh 2.0.1), because it is lacking a simple #-sign in the formatter. The working code is this:
HoverTool(tooltips=[('date', '#DateTime{%F}')],
formatters={'#DateTime': 'datetime'})

I have created a wrapper for ScatterPlot in bokeh.
class Visualization():
WIDTH = 1000
TOOLS = "pan,wheel_zoom,box_zoom,reset,save"
class ScatterChart(Visualization):
def __init__(self, data, spec:Dict):
self.data = data
self.x_column = spec["x_axis"]
self.y_column = spec["y_axis"]
self.series_ = spec["series_column"]
self.xlabel = spec['xlabel']
self.ylabel = spec['ylabel']
self.title = spec['title']
def prepare_data(self):
# Get Axis Type
self.xtype = 'datetime' if self.data.dtypes[self.x_column].type is np.datetime64 else 'linear'
self.ytype = 'datetime' if self.data.dtypes[self.x_column].type is np.datetime64 else 'linear'
return self.data
def render(self):
df_ = self.prepare_data()
format_= {}
tool_tip=[]
# For axis
for col in [self.x_column, self.y_column , self.series_]:
if self.data.dtypes[col].type is np.datetime64:
format_['#' + str(col) ] = "datetime" # formatter
tool_tip.append(tuple([str(col) , '#' + str(col) + '{%F}'])) # tool-tip
else:
format_['#' + str(col) ] = "numeral" #
tool_tip.append(tuple([str(col) , '#' + str(col)]))
# print(format_)
# print(tool_tip)
# Add Hover parameters
hover = HoverTool(tooltips= tool_tip
, formatters=format_ )
p=figure(
width = super().WIDTH,
height = 500,
x_axis_label = self.xlabel,
x_axis_type=self.xtype,
y_axis_label = self.ylabel,
y_axis_type=self.ytype,
title = self.title,
tools = super().TOOLS
)
# Get Only Top 10 groups/series to display
for value, color in zip(islice(self.data.groupby(by=[self.series_]
)[self.series_].count().sort_values(ascending=False).rename('cnt').reset_index()[self.series_].tolist(), 10), Category10[10]):
p.scatter(
x=self.x_column,
y=self.y_column,
source=df_.loc[(df_[self.series_]==value)],
color=color,
legend_group=self.series_
)
p.add_tools(hover)
p.toolbar.logo = None
p.legend.location = "top_left"
p.legend.click_policy="hide"
return p
# end of ScatterChart
This is how I initialize this
from visualization import ScatterChart
sc = ScatterChart(
df,
{'x_axis' :'ts',
'y_axis': 'Discus',
'series_column': 'Competition',
'xlabel':'Discus',
'ylabel':'Javeline',
'title':'Discus Vs Javeline'
})
d = sc.render()
show(d)