A code needs to be continued...(Python with Tkinter) - python-2.7

Question

This code is a simplified typing game, but I can't continue. The features required are:
Please don't use classes but just use FP;
When 5 random characters appear after you click the button, the 5 characters drop with a speed of 5 pixel/second, and meanwhile, you hit your keyboard to strike them. For every successful hit, your score wins by 10, and the character being hit will disappear. If not successful, they continue to drop untill the bottom edge of the canvas.
Below is part of my code, I've tried several times, but couldn't make it. How can I continue? Many thanks!
from Tkinter import *
from time import *
import string
import random
root = Tk ( )
root.title("Typing")
cvs = Canvas ( root , width=400 , height=350 , background="White" )
def Start():
s=random.sample("string.ascii_letters",5)
cvs.delete("rand")
return cvs.create_text(200,50,text=s,tags='rand',font=('Courier New',36,'normal'))
Button(root,text="Start",command=Start,width=30).pack()
cvs.pack ( )
root.mainloop ( )

Answer 1

You can animate an object by writing a function that draws one frame of animation, and then schedules itself to be called again in the future.
For example, to move a single object down the screen at five pixels a second you can use a function like this:
def animate(cvs, object_id):
# move down five pixels
cvs.move(object_id, 0, 5)
# call this function again in one second
# if the object is still on the screen
(x0,y0) = cvs.coords(object_id)
if y0 < cvs.winfo_height():
cvs.after(1000, animate, cvs, object_id)
You will have to modify that to handle more than one character, or call it once for each character. That decision is left up to you, this just illustrates the general technique.
Next, you can set up a binding to the <KeyPress> event, look at the character that was pressed, and if it matches something on the screen you can delete it. One simple way to keep track of what's on the screen is to map the characters to their canvas ids.
For example:
chars = {}
for char in random.sample(string.ascii_letters, 5):
obj_id = cvs.create_text(...)
chars[char] = obj_id
Now you'll have a dictionary that looks like:
{"a": 1, "X", 2, "y", 3, "f", 4, "B", 5}
You can now move or delete each canvas item by id.