Choosing a file in Python3

You need to import filedialog first, you can do it as follows:

from  tkinter import *
from tkinter import filedialog

root = Tk()

root.filename =  filedialog.askopenfilename(initialdir = "/", title = "Select file")
print (root.filename)

root.mainloop()

You can try something like this:

from  tkinter import *
root = Tk()
root.filename =  filedialog.askopenfilename(initialdir = "E:/Images",title = "choose your file",filetypes = (("jpeg files","*.jpg"),("all files","*.*")))
print (root.filename)
root.withdraw()

You're looking for tkinter.filedialog as noted in the docs.

from tkinter import filedialog

You can look at what methods/classes are in filedialog by running help(filedialog) in the python interpreter. I think filedialog.LoadFileDialog is what you're looking for.