title: Python Tkinter - Get value from mutliple checkboxes
body: <p>I am creating a Tkinter application where trying to get value from multiple checkboxes. I am able to create the checkboxes but not able to retrieve the value .i.e. checked or not checked checkboxes.</p>
  
  <p><strong>Requirement:</strong></p>
  
  <p>I need to loop through all checkbox variables to identify the checked ones.</p>
  
  <pre><code>import openpyxl
  import sys
  import pandas as pd
  from Tkinter import *
  import ttk
  import tkFont
  
  
  reload(sys)
  sys.setdefaultencoding('utf8')
  
  top = Tk()
  notebook = ttk.Notebook(top)
  notebook.grid(row=1, column=0, columnspan=1, sticky=W)
  frame1 = ttk.Frame(top)
  notebook.add(frame1, text='TAB1')
  s = ttk.Style()
  s.theme_use('clam')
  helv36 = tkFont.Font(family='Helvetica', size=12, weight=tkFont.BOLD)
  
  wb = openpyxl.load_workbook('File',data_only=True)
  ws = wb['Sheet1']
  
  mylist = []
  mylist1 = []
  for col in ws['A']:
       mylist.append(col.value)
  for col in ws['B']:
      mylist1.append(col.value)
  
  mylist = [str(item) for item in mylist]
  mylist1 = [str(item) for item in mylist1]
  
  i=2
  for name in mylist:
      Label(frame1, text="col1",
            borderwidth=1,font=helv36).grid(row=1)
      Label(frame1, text=name,
                    borderwidth=1).grid(row=i)
      i +=1
  
  
  i =2
  for name in mylist1:
      Label(frame1, text="col2",
            borderwidth=1,font=helv36).grid(row=1, column=1)
      Label(frame1, text=name,
            borderwidth=1).grid(row=i,column=1)
      val = IntVar()
      val = "v" + str(i)
      c_val = Checkbutton(frame1, variable=val)
      c_val.grid(row=i, column=2,sticky = W)
      i +=1
  
  
  ***def chkbox_checked():
      #Need to loop to get checked checkboxes***
  
  
  B200 = Button(frame1, text ="Check", command = chkbox_checked,font=helv36, bg='orange')
  B200.grid(row=100)
  top.mainloop()
  </code></pre>