Checkbuttons not properly aligning in Tkinter - python-2.7

Question

I am a Biological Engineering student working on a Capstone project in my university, and part of this project requires a little bit of coding. None of our group members knew how to code, so I've taken it upon myself to learn python and attempt to create a GUI using Tkinter. Given the reason for coding, I am extremely new to programming and thus, as a forewarning, my code is probably rather poorly written.
So to get to the point; I am having a problem getting my Checkbuttons to properly align. Essentially what happens is that the first Checkbutton group is aligned on rows 3-6 (I think, not 100% sure but they are where I want them) in column 0. I then created a second Checkbutton group in column 1, and I want the Checkbuttons to begin back at row 3-whatever, but instead they start at row 7 and span until whenever. This happens for each subsequent Checkbutton group I make.
The code is as follows:
import sys
from Tkinter import *
import tkMessageBox
import tkFileDialog
from PIL import ImageTk, Image
root = Tk()
root.geometry('900x700')
root.title('IBID 2.0')
ilabel1 = Label(root, text=' Measurement',font=("Bold",18)).grid(row=1,column=0)
datatype = {'Joint Angle' : 0,
'Joint Acceleration' : 0,
'Ground Reaction Force' : 0,
'Muscle Activation' : 0
}
for measure in datatype:
datatype[measure] = IntVar()
dt_cb = Checkbutton(root, text=measure, variable=datatype[measure])
dt_cb.grid(column=0, sticky='W', padx=20)
ilabel2 = Label(root, text='Muscle Group(s)',font= ("Bold",18),padx=30).grid(row=1,column=1)
emg_groups = {'Quadriceps' : 0,
'Hamstrings' : 0,
'Calves' : 0
}
for measure in emg_groups:
emg_groups[measure] = IntVar()
emg_cb = Checkbutton(root, text=measure, variable=emg_groups[measure])
emg_cb.grid(column=1, sticky='W', padx=20)
ilabel3 = Label(root, text='Ground Reaction Force',font=("Bold",18),padx=30).grid(row=1,column=2)
grf_groups = {'Ground Reaction Force' : 0,
'Gait' : 0,
}
for measure in grf_groups:
grf_groups[measure] = IntVar()
grf_cb = Checkbutton(root, text=measure, variable=grf_groups[measure])
grf_cb.grid(column=2, sticky='W', padx=40)
I did find a workaround where instead of using lists to create my Checkbuttons, I went ahead and made each button individually. I thought I might be able to clean up the code a little bit using lists, though I cannot find a way to put them all on the same line, I suppose. If I specify a row in the .grid(), then the options overlap one another.

Answer 1

Every time you call grid() without supplying a row Tkinter is automatically assuming you want to add it to a new row at the bottom:
wdgt.grid(row=0, column=0)
wdgt.grid(column=1) # row=1 is assumed here
Instead, you'll need to supply the row numbers to the new widgets you're trying to grid:
for i, measure in enumerate(emg_groups):
emg_groups[measure] = IntVar()
emg_cb = Checkbutton(root, text=measure, variable=emg_groups[measure])
emg_cb.grid(column=1, row=i+2, sticky='W', padx=20)
and:
for i, measure in enumerate(grf_groups):
grf_groups[measure] = IntVar()
grf_cb = Checkbutton(root, text=measure, variable=grf_groups[measure])
grf_cb.grid(column=2, row=i+2, sticky='W', padx=40)
Using enumerate() we get a tuple on each loop of the iteration, i being a 0 indexed counter, and of course measure being the object itself. Since you started your Label() at row 1 (you may want to change to start at row 0), we'll need to add 2 to the index each time through and then grid to that row number.