Python 3, Tkinter, trying to get 9 buttons on 3 different rows - python-3.x

Question

Ive just started using tkinter and have this so far:
from tkinter import *
BoardValue = ["-","-","-","-","-","-","-","-","-"]
window = Tk()
window.title("Noughts And Crosses")
window.geometry("250x250")
for b in BoardValue[0:3]:
btn = Button(window, text=b, relief=GROOVE, width=2).pack(side=LEFT)
for b in BoardValue[3:6]:
btn = Button(window, text=b, relief=GROOVE, width=2).pack(side=LEFT)
for b in BoardValue[6:9]:
btn = Button(window, text=b, relief=GROOVE, width=2).pack(side=LEFT)
window.mainloop()
I want 3 buttons on 3 rows, how can I do this?

Answer 1

There are two common solutions: one using grid, and one using pack with subframes for each row. There are other solutions but these are the most common. Of these two, when creating a grid of widgets, grid is the most natural solution.
Note: in both of the examples below, you can create the buttons in three separate loops if you want, but since the buttons are identical I chose to use a single loop to make the code a little easier to maintain (for example, if you decide to change the relief, you only have to change it in one line of code rather than three).
Using grid
You can use the grid geometry manager to align things in rows and columns. Since you can compute the row and column with simple math, you can reduce all of that code down to something like this:
for i, b in enumerate(BoardValue):
row = int(i/3)
col = i%3
btn = Button(window, text=b, relief=GROOVE, width=2)
btn.grid(row=row, column=col, sticky="nsew")
You may want to add a weight to the rows and columns if you want them to grow and shrink equally when you resize the window.
grid has an advantage over pack when building a matrix like this, since each cell is guaranteed to be the same size.
Using pack
If you know that each button will be the same width, you can use pack in combination with subframes. Pack the subframes along the top, and the buttons along the left or right. Again, you can use a little math to know when a new row is starting.
It would look something like this:
for i, b in enumerate(BoardValue):
if i%3 == 0:
row_frame = Frame(window)
row_frame.pack(side="top")
btn = Button(row_frame, text=b, relief=GROOVE, width=2)
btn.pack(side="left")
Using pack may not be the right choice if buttons could be different sizes, since there are no actual columns using this method.

Answer 2

The simple answer is to put the buttons in frames so you can control the packing order. E.g.;
i=0
for f in range(3):
frame[f] = Frame(window).pack(side=TOP)
for b in range(3):
btn[i] = Button(frame[f], text=i, relief=GROOVE, width=2).pack(side=LEFT)
i+=1
I've put the button & frame objects into lists in case you need to access the button objects later; you were overwriting your handles in the original code.