Using on_change() method in bokeh (python code)

Question

The purpose of the below code is to generate TextInput() boxes based on an input in a TextInput() box and extract values from the new TextInput() boxes The problem is that I am having difficulty understanding the on_change() function. After typing into the first box I get a number of boxes (which I will call 'generated box'). I am able to print 'Printing' whenever I type into a generated box so I know that the on_change() method is working in a loop for all the generated boxes but I have been unable to extract the User input in any of the generated boxes.

from bokeh.client import push_session
from bokeh.io import curdoc
from bokeh.models import ColumnDataSource, TextInput
from bokeh.layouts import gridplot, row, column 
curdoc().clear()
NR=TextInput() #Input no. of rows in this
N=[] #stores the TextInput boxes NR times
value=0
def PushSes(x):
      rowe = row(x)
      curdoc().add_root(rowe)

def update(attr,new,old):
      global value
      global N
      value1= int(NR.value)
      for i in range (value1):
            N.append(TextInput()) #N stores the TextInput boxes

      for i in N:
            i.on_change('value',update1)

      curdoc().clear()
      PushSes(N)

def update1(attr,new,old):
      print('Printing')
NR.on_change('value',update)
val=[] #stores value from the first row
session=push_session(curdoc())
PushSes(NR)
session.show()
session.loop_until_closed()

Infi · Accepted Answer · 2017-08-07 05:11:12Z

2

Solved the problem -

def update1(attr,new,old):
      print('Printing')
      print(old)

In a loop old has the values and prints in order of the typing. Thanks to @bigreddot for the hint.

edited Aug 7, 2017 at 5:11

answered Aug 7, 2017 at 4:57

Infi

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Comments

bigreddot · Accepted Answer · 2017-07-30 15:32:21Z

1

The new parameter passed to update1 by Bokeh when it calls the callback, has the new value of the text box.

answered Jul 30, 2017 at 15:32

bigreddot

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