What key pressed? - Printable Version

What key pressed? - Printable Version

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What key pressed? - ian - Jul-29-2018

I test the code below but not sure how to catch non-ASCII key, like Enter, Esc and so on. Thanks

import msvcrt
while True:
    if msvcrt.kbhit():
        print(msvcrt.getch())

RE: What key pressed? - ichabod801 - Jul-29-2018

Try playing with this:

import msvcrt
while True:
    if msvcrt.kbhit():
        print(repr(msvcrt.getch()))

Some trial and error should get you the info you need.

RE: What key pressed? - snippsat - Jul-29-2018

>>> import msvcrt
>>> help(msvcrt.getch)
Help on built-in function getch in module msvcrt:
 
getch()
    Read a keypress and return the resulting character as a byte string.
     
    Nothing is echoed to the console. This call will block if a keypress is
    not already available, but will not wait for Enter to be pressed. If the
    pressed key was a special function key, this will return '\000' or
    '\xe0'; the next call will return the keycode. The Control-C keypress
    cannot be read with this function.

Can do a test,use repr() to see what really going on.

import msvcrt
 
while True:
    character = msvcrt.getch()
    print(repr(character))
    if character == b'q':
        break

So i get b'\x00' normal key and b'\xe0' for function keys.
Then can write it like this.

import msvcrt
import sys

while True:
    ch = msvcrt.getch()
    if ch in b'\x00':
        ch = msvcrt.getch() # Second call returns the scan code
    if ch in b'\xe0':
        ch = msvcrt.getch() # Second call Function keys
    if ch == b'q':
       sys.exit()
    else:
       print(f'Key Pressed: {ch}')

Output:E:\div_code        
λ python scan.py   
Key Pressed: b'h'  
Key Pressed: b'e'  
Key Pressed: b'l'  
Key Pressed: b'l'  
Key Pressed: b'o'  
Key Pressed: b'\x1b
Key Pressed: b'\x1b
Key Pressed: b'\x1b
Key Pressed: b'\r' 
Key Pressed: b'\r' 
Key Pressed: b'\r'

3 times Esc and 3 times Enter after hello.
Key Scan Codes
So Esc(27) and Enter(13).

>>> k = b'\x1b'
>>> ord(k)
27
>>> k = b'\r'
>>> ord(k)
13
>>> if ord(b'\r') == 13:
...     print('Enter key was pressed')
...     
Enter key was pressed