iPyWidget with date slider?

Question

I am wondering if there's an easy way to build an iPyWidget with a datetime slider. Right now it is easy to slide over integer or floating point ranges (e.g. numbers 1-10, decimals 0.01, 0.02, ...).

I imagine you could convert dates to floats or integers, build some sort of slider using these, and then convert back to dates for the display labels on the slider. However, this seems clunky. Does anyone have a smoother solution?

Answer 1

I had the same issue recently. I had to write my own class to do a daterange picker. Here is my code:

import pandas as pd
import ipywidgets as widgets
from IPython.display import display

class DateRangePicker(object):
    def __init__(self,start,end,freq='D',fmt='%Y-%m-%d'):
        """
        Parameters
        ----------
        start : string or datetime-like
            Left bound of the period
        end : string or datetime-like
            Left bound of the period
        freq : string or pandas.DateOffset, default='D'
            Frequency strings can have multiples, e.g. '5H' 
        fmt : string, defauly = '%Y-%m-%d'
            Format to use to display the selected period

        """
        self.date_range=pd.date_range(start=start,end=end,freq=freq)
        options = [(item.strftime(fmt),item) for item in self.date_range]
        self.slider_start = widgets.SelectionSlider(
            description='start',
            options=options,
            continuous_update=False
        )
        self.slider_end = widgets.SelectionSlider(
            description='end',
            options=options,
            continuous_update=False,
            value=options[-1][1]
        )

        self.slider_start.on_trait_change(self.slider_start_changed, 'value')
        self.slider_end.on_trait_change(self.slider_end_changed, 'value')

        self.widget = widgets.Box(children=[self.slider_start,self.slider_end])

    def slider_start_changed(self,key,value):
        self.slider_end.value=max(self.slider_start.value,self.slider_end.value)
        self._observe(start=self.slider_start.value,end=self.slider_end.value)

    def slider_end_changed(self,key,value):
        self.slider_start.value=min(self.slider_start.value,self.slider_end.value)
        self._observe(start=self.slider_start.value,end=self.slider_end.value)

    def display(self):
        display(self.slider_start,self.slider_end)

    def _observe(self,**kwargs):
        if hasattr(self,'observe'):
            self.observe(**kwargs)

def fct(start,end):
    print start,end

Using it is relatively straightforward:

w=DateRangePicker(start='2016-08-02',end="2016-09-02",freq='D',fmt='%Y-%m-%d')
w.observe=fct
w.display()

Enjoy ;-)