如何同时在Python Tkinter中读取csv？

Question

I have some questions to you. My first question is I read csv file with import_csv_data function but before I read the data although I have made definition like "global df" it says df is not defined. If I create a df like df = pd.DataFrame(Columns=["X","Y"]) , this time OptionMenu show X and Y. If i want to show columns of my DataFrame i need to remove df = pd.DataFrame(Columns=["X","Y"]) and then i need to run code again. And i have one questiong connected with this question is when i read csv file, to see last df i need to close Window. So i want to read csv file and i want the program to memorize at the same time. The second question is when i changed the SelectedValue on OptionMenu i want to get the SelectedValue -selected column name- and show on tk.Button(Drop Column + SelectedValue) < in short i want to get the column name on OptionMenu and show the name on Button at the same time. Third question is i can not fit button or text or label to Frame. It is limitting me i have added a photo that describe that question.[Here is image url. > https://ibb.co/wrkcdfK ] Thank you.

def _quit():
    root.quit()     # stops mainloop
    root.destroy()  # this is necessary on Windows to prevent
                    # Fatal Python Error: PyEval_RestoreThread: NULL tstate
def option_changed(*args):
    global SelectedValue
    SelectedValue = selection.get()
    print(SelectedValue)

def hello():
    print("hello!")

def import_csv_data():
    global v
    global df 
    global a
    csv_file_path = askopenfilename()
    print(csv_file_path)
    v.set(csv_file_path)
    df = pd.read_csv(csv_file_path)
    a = csv_file_path

def removenans():
    print("Merhaba")
    print(df.head())
    df = pd.read_csv(csv_file_path)

def plotthefigure():
    df.dropna(inplace=True,axis=0)
    df.Sex = [1 if i=="female" else 0 for i in df.Sex]
    plt.figure(figsize=[6,5])
    plt.plot(range(len(df["Sex"])),df["Sex"])
    plt.title("Age vs Sex")
    # Plot window name
    plt.gcf().canvas.set_window_title("Plot Frame")

#Switching Frames
def raise_frame(frame):
    frame.tkraise()


# Opening new window
def aboutmenudef():
    window = tk.Toplevel(root)

def printdf():
    tk.Label(MainFrame,textvariable=df.head()).grid(row=6, 
            columnspan=7, 
        sticky='WE',padx=5, pady=5, ipadx=5, ipady=5)

root = tk.Tk()
root.wm_title("Machine Learning Implementer")

# FRAMES # 
#
MainFrame = Frame(root)
AboutFrame = Frame(root)
HelpFrame = Frame(root)
#
for frame in (MainFrame,AboutFrame,HelpFrame):
    frame.grid(row=0, column=0, sticky=NSEW)


v = tk.StringVar()

entry = tk.Entry(MainFrame,
                 textvariable=v).grid(row=0,
                               column=1,
                               ipadx=100)

head = tk.StringVar()
tk.Label(MainFrame,textvariable=head).grid(row=3, columnspan=2, 
        sticky='WE',padx=5, pady=5, ipadx=5, ipady=5)


tk.Label(AboutFrame,
         text="About Us").grid(row=0,column=0)

tk.Label(MainFrame,text="File Path").grid(row=0,
        column=0)

mainlabel = Label(MainFrame,text="DF Columns").grid(row=5,
     column=0)

###---------------------- BUTTON ----------------------###

tk.Button(MainFrame,
          text="          Read CSV        ",
          command=removenans).grid(row=1,
                       column=0)

tk.Button(MainFrame,
          text="  Drop Column\n  "+SelectedValue,
          command=removenans).grid(row=2,
                       column=0)

tk.Button(MainFrame,
          text="Remove NaN Values",
          command=removenans).grid(row=3,
                       column=0)

tk.Button(MainFrame,
          text="   Print Head of DF   ",
          command=printdf).grid(row=4,
                         column=0)
tk.Button(MainFrame,
          text="   Scale Parameters   ",
          command=printdf).grid(row=10,
                         column=0)
tk.Button(MainFrame,
          text="Plot the Graph",
          command=plotthefigure).grid(row=0,
                           column=2)

###---------------------- CHECKBOX ----------------------###

var = IntVar()
c = Checkbutton(root,text="Independent",variable = var)
c.grid(row=3, column=3)
c.config(state=DISABLED)

###---------------------- MENU & TOOLBARS ----------------------###

menubar = Menu(root)

# FILE MENU #

filemenu = Menu(menubar,tearoff=0)
filemenu.add_command(label="Open CSV File",
                     command=import_csv_data)
#filemenu.add_command(label="Save",
#                     command=hello)
filemenu.add_separator()
filemenu.add_command(label="Exit",
                     command=_quit)
menubar.add_cascade(label="   File   ",
                    menu=filemenu)

# MENU PLOT SECTION #

plotmenu = Menu(menubar,tearoff=0)
plotmenu.add_command(label="Open Plot",
                     command=hello)
#plotmenu.add_separator() 
plotmenu.add_command(label="Close Program",
                     command=_quit)
menubar.add_cascade(label="   Plot   ",
                    menu=plotmenu)

# HELP #

helpmenu = Menu(menubar,tearoff=0)
helpmenu.add_command(label="Help Index",
                     command=hello)
menubar.add_cascade(label="   Help   ",
                     menu=helpmenu)

# ABOUT #

aboutmenu = Menu(menubar,tearoff=0)
aboutmenu.add_command(label="About",
                      command=lambda:raise_frame(AboutFrame))
menubar.add_cascade(label="   About   ",
                    menu=aboutmenu)
root.config(menu=menubar)

# OPTION MENU # 

selection = StringVar(MainFrame)
selection.set("-") # default value
selection.trace("w", option_changed)

w = OptionMenu(MainFrame, selection, *df.columns).grid(row=2,
              column=1)

#

root.geometry("800x550")

raise_frame(MainFrame)
root.mainloop()

Answer 1

For the first question i have created a new button named Read Csv, so after i have browsed the csv data i read it with a button. For second question i couldnt do this. But i have found something about label with label.config then you can change the value with a def function that you connected with a button for example. For the last question, i guess it was about the root.geometry() i have changed it to root.geometry("1200x800") and i have defined it on the top one section below of root = Tk() .... If you have any questions about tkinter you can ask.