How to left justify Python tkinter grid columns while filling entire cell

If you want the text in a label to be left-aligned, use the anchor option. It takes a string representing a point on a compass (eg: "w" = "west", meaning the text is anchored to the left):

for col in row:
    Label(..., anchor="w").grid(...)

For any grid of geometry, add option sticky="W", for example,

self.tableDataFrame.grid(sticky="W", row=0, column=0)