using ipywidgets SelectMultiple on a dataframe - dataframe

Question

import pandas as pd
import numpy as np
import ipywidgets as widgets
from IPython.display import display
a = ['Banking', 'Auto', 'Life', 'Electric', 'Technology', 'Airlines',
'Healthcare']
df = pd.DataFrame(np.random.randn(7, 4), columns = list('ABCD'))
df.index = a
df.head(7)
dropdown = widgets.SelectMultiple(
options=df.index,
description='Sector',
disabled=False,
layout={'height':'100px', 'width':'40%'})
display(dropdown)
I want to create a function where I can filter the df by Sector. i.e say I select Airlines, Banking and Electric from the display(dropdown) and it returns a dataframe of the selected sectors only.

Answer 1

Try something like this, I have used a global variable to demonstrate in this case, but I would normally wrap up the functionality in a class so you always have access to the filtered dataframe.
Rather than use interact I have used .observe on the Selection widget.
import pandas as pd
import numpy as np
import ipywidgets as widgets
from IPython.display import display, clear_output
a = ['Banking', 'Auto', 'Life', 'Electric', 'Technology', 'Airlines',
'Healthcare']
df = pd.DataFrame(np.random.randn(7, 4), columns = list('ABCD'), index=a)
filtered_df = None
dropdown = widgets.SelectMultiple(
options=df.index,
description='Sector',
disabled=False,
layout={'height':'100px', 'width':'40%'})
def filter_dataframe(widget):
global filtered_df
selection = list(widget['new'])
with out:
clear_output()
display(df.loc[selection])
filtered_df = df.loc[selection]
out = widgets.Output()
dropdown.observe(filter_dataframe, names='value')
display(dropdown)
display(out)