Problem in code while using Python msvcrt

Question

Only getting a blank screen, what is wrong?

import msvcrt
while(1):
  choice = msvcrt.getch()
  if(choice =='a'):
      print('a')
  elif(choice =='s'):
      print('s')

I wanted to take single character input from the user without pressing enter — , Mar 22 '20 at 10:04
Your code looks fine to me? https://www.oreilly.com/library/view/python-standard-library/0596000960/ch12s11.html — Aiyion.Prime, Mar 22 '20 at 10:20
@Aiyion.Prime The reference you provide is to a book about Python 2. — BoarGules, Mar 22 '20 at 12:18

score 2 · Accepted Answer · answered Mar 22 '20 at 12:10

Your problem is that getch() returns a byte not a string. If you press a the value of choice is the bytestring b'a' which is not the same as the string 'a'. Consider this:

>>> choice = b'a'
>>> choice == 'a'
False
>>> choice.decode() == 'a'
True

And your screen is remaining blank because neither if-condition can ever be true, and you have no catch-all else: clause. You could have discovered this for yourself simply by printing out the value of choice.

Change your test from

if choice =='a':

to

if choice.decode() == 'a':

(and do drop those unnecessary parens from your if tests).

In Python 2, your original code would have worked the way you expect.

Problem in code while using Python msvcrt

1 Answers1