getting the value to the Entry using tkinter - python-2.7

Question

I want to know how to display the values using Entry? i mean for instance if i have a function like:
def open():
path=tkFileDialog.askopenfilename(filetypes=[("Image File",'.jpg')])
blue, green, red = cv2.split(path)
total = path.size
B = sum(blue) / total
G = sum(green) / total
R = sum(red) / total
B_mean1.append(B)
G_mean1.append(G)
R_mean1.append(R)
blue.set(B_mean1)
green.set(G_mean1)
red.set(R_mean1)
root = Tk()
blue_label = Label(app,text = 'Blue Mean')
blue_label.place(x = 850,y = 140)
blue = IntVar(None)
blue_text = Entry(app,textvariable = blue)
blue_text.place(x = 1000,y = 140)
green_label = Label(app,text = 'Green Mean')
green_label.place(x = 850,y = 170)
green = IntVar(None)
green_text = Entry(app,textvariable = green)
green_text.place(x = 1000,y = 170)
red_label = Label(app,text = 'Red Mean')
red_label.place(x = 850,y = 200)
red = IntVar(None)
red_text = Entry(app,textvariable = red)
red_text.place(x = 1000,y = 200)
button = Button(app, text='Select an Image',command = open)
button.pack(padx = 1, pady = 1,anchor='ne')
button.place( x = 650, y = 60)
root.mainloop()
I have specified all the necessary imports and list variables. Still the value is not being displayed in the Entry field.
like if i get the value as :
blue mean = 37,
green mean = 36,
red mean = 41
and it will print in the console but not in the window. How can I achieve this?
Any suggestions are welcome!
Thanks for your supports!

Answer 1

Firstly I want to recommend that instead of using the place method you use the grid method. It is a lot faster and allows you to do things in a much more orderly fashion - especially in this application. Note that there are other geometry managers - like pack - which are good in yet other instances. Anyways, your GUI:
root = Tk()
blue_label = Label(root, text="Blue mean:")
blue_label.grid(row=1, column=1, sticky="w")
blue_entry = Entry(root)
blue_entry.grid(row=1, column=2)
green_label = Label(root, text="Green mean:")
green_label.grid(row=2, column=1, sticky="w")
green_entry = Entry(root)
green_entry.grid(row=2, column=2)
red_label = Label(root, text="Red mean:")
red_label.grid(row=3, column=1, sticky="w")
red_entry = Entry(root)
red_entry.grid(row=3, column=2)
root.mainloop()
That makes your GUI display nicely and without the manual geometry. Note that sticky just sets how the text is justified ("w" means west, and so the text justifies left).
Now, for actually displaying the text, all you have to do is:
blue_entry.insert(0, "blue-mean-value")
green_entry.insert(0, "green-mean-value")
red_entry.insert(0, "red-mean-value")
And if you are overwriting any text that is already there just do:
blue_entry.delete(0, END) # And green_entry and red_entry