detect key press in python

Question

I am making a stopwatch type program in python and I would like to know how to detect if a key is pressed  such as p for pause and s for stop   and I would not like it to be something like raw input that waits for the user s input before continuing execution  Anyone know how to do this in a while loop   Also  I would like to make this cross-platform  but if that is not possible  then my main development target is linux

User · Answer

I would suggest you use PyGame and add an event handle   http   www pygame org docs ref event html

User · Answer

For Windows you could use msvcrt like this      import msvcrt    while True         if msvcrt kbhit               key   msvcrt getch              print key      just to show the result

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You don t mention if this is a GUI program or not  but most GUI packages include a way to capture and handle keyboard input  For example  with tkinter  in Py3   you can bind to a certain event and then handle it in a function  For example  import tkinter as tk  def key handler event None       if event and event keysym in   s    p             do something   r   tk Tk   t   tk Text   t pack   r bind   lt Key gt    key handler  r mainloop    With the above  when you type into the Text widget  the key handler routine gets called for each  or almost each  key you press

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More things can be done with keyboard module  You can install this module using pip install keyboard Here are some of the methods   Method   1  Using the function read key    import keyboard  while True      if keyboard read key       quot p quot           print  quot You pressed p quot           break  This is gonna break the loop as the key p is pressed   Method  2  Using function wait  import keyboard  keyboard wait  quot p quot   print  quot You pressed p quot    It will wait for you to press p and continue the code as it is pressed   Method  3  Using the function on press key  import keyboard  keyboard on press key  quot p quot   lambda   print  quot You pressed p quot     It needs a callback function  I used   because the keyboard function returns the keyboard event to that function  Once executed  it will run the function when the key is pressed  You can stop all hooks by running this line  keyboard unhook all     Method  4  This method is sort of already answered by user8167727 but I disagree with the code they made  It will be using the function is pressed but in an other way  import keyboard  while True      if keyboard is pressed  quot p quot            print  quot You pressed p quot           break  It will break the loop as p is pressed   Notes   keyboard will read keypresses from the whole OS  keyboard requires root on linux

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For those who are on windows and were struggling to find an working answer here s mine  pynput  from pynput keyboard import Key  Listener  def on press key       print   0  pressed  format          key    def on release key       print   0  release  format          key       if key    Key esc            Stop listener         return False    Collect events until released with Listener          on press on press          on release on release  as listener      listener join     The function above will print whichever key you are pressing plus start an action as you release the  esc  key  The keyboard documentation is here for a more variated usage   Markus von Broady highlighted a potential issue that is  This answer doesn t require you being in the current window to this script be activated  a solution to windows would be   from win32gui import GetWindowText  GetForegroundWindow current window    GetWindowText GetForegroundWindow     desired window name    Stopwatch   Whatever the name of your window should be   Infinite loops are dangerous  while True   Don t rely on this line of code too much and make sure to adapt this to your project      if current window    desired window name           with Listener              on press on press              on release on release  as listener              listener join

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Use this code for find the which key pressed  from pynput import keyboard  def on press key       try          print  alphanumeric key  0  pressed  format              key char       except AttributeError          print  special key  0  pressed  format              key    def on release key       print   0  released  format          key       if key    keyboard Key esc            Stop listener         return False    Collect events until released with keyboard Listener          on press on press          on release on release  as listener      listener join

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key   cv2 waitKey 1    This is from the openCV package  It detects a keypress without waiting

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Use PyGame to have a window and then you can get the key events   For the letter p   import pygame  sys import pygame locals  pygame init   BLACK    0 0 0  WIDTH   1280 HEIGHT   1024 windowSurface   pygame display set mode  WIDTH  HEIGHT   0  32   windowSurface fill BLACK   while True      for event in pygame event get            if event key    pygame K p    replace the  p  to whatever key you wanted to be pressed              pass  Do what you want to here         if event type    pygame locals QUIT               pygame quit                sys exit

User · Answer

As OP mention about raw input - that means he want cli solution  Linux  curses is what you want  windows PDCurses   Curses  is an graphical API for cli software  you can achieve more than just detect key events   This code will detect keys until new line is pressed   import curses import os  def main win       win nodelay True      key        win clear                       win addstr  Detected key        while 1                    try                              key   win getkey                       win clear                              win addstr  Detected key               win addstr str key               if key    os linesep                break                    except Exception as e               No input               pass           curses wrapper main

User · Answer

So I made this   kind of game   based on this post  using msvcr library and Python 3 7    The following is the  main function  of the game  that is detecting the keys pressed     Requiered libraries - - - - import msvcrt   - - - - - - - - - - - - - -   def  secret key self         Get the key pressed by the user and check if he she wins       bk   chr 10     -  25   chr 10       while True           print bk    Press any key s     bk           asks the user to type any key s           kp   str msvcrt getch    replace  b        replace                    Store key s value           if r  xe0  in kp              kp    str msvcrt getch    replace  b        replace                        Refactor the variable in case of multi press           if kp    r  xe0 x8a                 If user pressed the secret key  the game ends                 x8a is CTRL F12  that s the secret key               print bk    CONGRATULATIONS YOU PRESSED THE SECRET KEYS  a    bk              print  Press any key to exit the game               msvcrt getch               break         else              print      You pressed     kp       that s not the secret key s  n               if self select continue       n                   if self secondary options                        self  main menu                   break   If you want the full source code of the porgram you can see it or download it from here   The Secret Key Game  GitHub    note  the secret keypress is  Ctrl F12   I hope you can serve as an example and help for those who come to consult this information

User · Answer

Python has a keyboard module with many features  Install it  perhaps with this command     pip3 install keyboard   Then use it in code like   import keyboard    using module keyboard while True     making a loop     try     used try so that if user pressed other than the given key error will not be shown         if keyboard is pressed  q       if key  q  is pressed              print  You Pressed A Key                break    finishing the loop     except          break    if user pressed a key other than the given key the loop will break

[python] detect key press in python?

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