3

I'm attempting to write a program that involves the use of a coin flip, heads or tails, but so that it will print 'heads' then be replaced by 'tails' and continue doing this until it decides on an answer.

At the moment, when I run the program, it prints the 'heads' or 'tails' on the next line every time. This happens on both Idle and Terminal.

I've tried using carriage return (\r), backspace (\b) and sys.stdout.write() and .flush() but neither are working, it just keeps printing on the next line.

Is there either another way of erasing what's been printed or is there other software I can use? Here is my code:

import time
import random

offset = random.randint(0,1)

for i in range (0, 20+offset):
    if i % 2 == 0:
        print("Heads")
    else:
        print("Tails")
    print("\r")
    time.sleep(0.1)
revolve
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  • 3

1 Answers1

5

print writes a \n character to the end, therefore you need to modify that if you want to keep on the same line.

import time
import random

offset = random.randint(0,1)

for i in range (0, 20+offset):
    if i % 2 == 0:
        print("Heads", end='')
    else:
        print("Tails", end='')
    print("\r", end='')
    time.sleep(0.1)

Edit: That only works for python 3, If you want to use that in python 2 then you need to write to sys.stdout

import time
import random
import sys  

offset = random.randint(0,1)

for i in xrange(0, 20+offset):
    if i % 2 == 0:
        sys.stdout.write("Heads")
    else:
        sys.stdout.write("Tails")
    time.sleep(0.1)
    sys.stdout.flush()  
    sys.stdout.write("\r")

I'm aware this might not be the fastest implemention, but It works, I could type a faster approach later

no_name
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  • This is the most specific answer. Removing mine. – Tim Pietzcker Feb 14 '15 at 11:13
  • I'm still getting a space between lines, there's no change when I do this on idle and terminal is now saying that there is an invalid syntax on line 8 - print("Heads", end='') – revolve Feb 14 '15 at 11:22
  • This code will never work on IDLE, due to some weird '\r' mechanism implemented in IDLE, try using it from a terminal, or the python exe – no_name Feb 14 '15 at 11:59
  • Terminal is working now with the second program, even though I'm in python 3 and not 2, thank you :D – revolve Feb 14 '15 at 12:15