Tkinter Label doesn't update

Question

Can anyone shed some light on why this wouldn't update label3 ?

self.label3Text = StringVar()
self.label3Text.set("0/0")
self.label3 = Label(textvariable=self.label3Text)
self.label3.pack()

---

for root,dirs,filenames in os.walk(self.path):
    #iterate through the files
    num_files = len(filenames)
    i = 0
    for f in filenames:
        #if the file is a text file
        if ".txt" in f:
            #define the path of this new file as the datalog folder plus the filename
            file_path = os.path.join(self.path,f)
            #write the correct data to the csv file for this file
            self.addRows(f,file_path)
            i = i + 1
            out = str(i) + "/" + str(num_files) + " files processed"
            self.label3Text.set(out)

Answer 1

Ok - so the answer was that I needed to update my root window! By calling window.update(), I solved the problem. Where window was declared as: window = Tk()

Just adding this in case someone else stumbles across this question.