Python interactive visualization able to write selected data to dataframe?

Question

I am looking for an interactive visualization python tool that would allow me to select a number of data points and then write only those data points into a new data frame, numpy array, etc. For example, I'd like to visualize all of the equity trades a desk of traders did in one day along with tick-by-tick price data (y axis price, x axis time) then select a subset of them and send them to a new dataframe for further processing. Does anything like that exist? I thought Holoviews might but haven't figured it out yet. Thanks, Colin

score 0 · Accepted Answer · answered Jan 06 '18 at 09:38

Indeed you can do this with Holoviews. In this example it is used in combination with Bokeh. Save the script file, open a command window in the directory of the file and execute: "bokeh serve --myscript.py --show". The "arr" in the code is the array of the selected datapoints.

import numpy as np
import holoviews as hv
import holoviews.plotting.bokeh

renderer = hv.renderer('bokeh')

points = hv.Points(np.random.randn(1000,2 )).opts(plot=dict(tools=['box_select', 'lasso_select']))
selection = hv.streams.Selection1D(source=points)

def selected_info(index):
    arr = points.array()[index]
    print(arr)
    if index:
        label = 'Mean x, y: %.3f, %.3f' % tuple(arr.mean(axis=0))
    else:
        label = 'No selection'
    return points.clone(arr, label=label).opts(style=dict(color='red'))

layout = points + hv.DynamicMap(selected_info, streams=[selection])

doc = renderer.server_doc(layout)
doc.title = 'HoloViews App'

Strictly you don't need holoviews, you can do this also with bokeh alone. There are examples on the bokeh website.

Python interactive visualization able to write selected data to dataframe?

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