i am new to Python. And I am trying to make a drop down menu which will have some options (eg 4 options). I also need a Ok button in the same window. The user needs to select an option and click on "Ok". I need only single selection. When the user clicks Ok after selection, the selected option should be put in an variable.
Please help me in this . It will be great if this can be done in Tkinter. :)

Post the code you have so far along with any problems.

You can use Tkinter that comes with the Python installation:

# using Tkinter's Optionmenu() as a combobox

    # Python2
    import Tkinter as tk
except ImportError:
    # Python3
    import tkinter as tk

def select():
    sf = "value is %s" % var.get()
    # optional
    color = var.get()
    root['bg'] = color

root = tk.Tk()
# use width x height + x_offset + y_offset (no spaces!)
root.geometry("%dx%d+%d+%d" % (330, 80, 200, 150))
root.title("tk.Optionmenu as combobox")

var = tk.StringVar(root)
# initial value

choices = ['red', 'green', 'blue', 'yellow','white', 'magenta']
option = tk.OptionMenu(root, var, *choices)
option.pack(side='left', padx=10, pady=10)

button = tk.Button(root, text="check value slected", command=select)
button.pack(side='left', padx=20, pady=10)


simple wxPyCode that does nothing, just a display!
import wx

class wxDemo(wx.Frame):
    def __init__(self, parent): 
        wx.Frame.__init__(self, parent, title='Demo Frame')
        self.panel = wx.Panel(self, -1)
        self.sizer = wx.BoxSizer(wx.VERTICAL)
        self.combo = wx.ComboBox(self.panel, choices=['Moja', 'Mbili', 'Tatu', 'Nne', 'Tano'])
        self.text = wx.TextCtrl(self.panel, wx.ID_ANY, style=wx.TE_MULTILINE)
        self.sizer.Add(self.combo, 0, wx.EXPAND)
        self.sizer.Add(self.text, 1, wx.EXPAND)
app = wx.App()
fr = wxDemo(None)