How to listen Key combination?

[521xueweihan]

Great library!

When I use the pynput I want to listen the key combination, Such as: ctrl+cmd

I can't find the way to do that,So I ask you for help.👻

[moses-palmer]

Thank you!

The listener does not maintain a list of the currently pressed keys---this would be a new, quite reasonable, feature.

You can however emulate that using the following snippet:

from pynput import keyboard

# The key combination to check
COMBINATION = {keyboard.Key.cmd, keyboard.Key.ctrl}

# The currently active modifiers
current = set()


def on_press(key):
    if key in COMBINATION:
        current.add(key)
        if all(k in current for k in COMBINATION):
            print('All modifiers active!')
    if key == keyboard.Key.esc:
        listener.stop()


def on_release(key):
    try:
        current.remove(key)
    except KeyError:
        pass


with keyboard.Listener(on_press=on_press, on_release=on_release) as listener:
    listener.join()

This works as expected, with the following caveat: If one of the modifier keys is pressed before the listener is started, it has to be released and pressed again for the program to detect it.

I will update the road map in the wiki.

[521xueweihan]

Thank you for your replay, I learn a lot 🙏

[arcadeperfect]

Hi,

Thanks for the lib

How can I combine your above example with a regular character to create a hotkey?

IE shift+ctrl+alt+x causes some code to execute.

Thanks

[gaoyaoxin]

@arcadeperfect

from pynput import keyboard

# The key combination to check
COMBINATION = {keyboard.Key.shift, keyboard.Key.ctrl, keyboard.Key.alt, keyboard.KeyCode.from_char('x')}

# The currently active modifiers
current = set()


def on_press(key):
    if key in COMBINATION:
        current.add(key)
        if all(k in current for k in COMBINATION):
            print('All modifiers active!')
    if key == keyboard.Key.esc:
        listener.stop()


def on_release(key):
    try:
        current.remove(key)
    except KeyError:
        pass


with keyboard.Listener(on_press=on_press, on_release=on_release) as listener:
    listener.join()

keyboard.KeyCode.from_char('x') or its alike works fine for alphanumeric keys.
Please note that the order of keys pressed is important. Beginning with alt and then x works fine while others may not.
In my point of view, this might have something to with system-built-in shortcuts which often combines ctrl, alt and shift. However, without shift, ctrl+alt+x works fine in any order.
Hope the designer (@moses-palmer) for this phenomenal package which can listen/monitor global keyboard events have some view on this!

[devxpy]

@moses-palmer How are you able to modify the current varialbe from a function. AFAIK, it's not possible to modify global variable from inside a function in python without explicity declaring global in your function definition.

https://stackoverflow.com/questions/4522786/modifying-a-global-variable-inside-a-function

[moses-palmer]

You cannot assign to a global variable unless declaring it using global, since that would instead introduce it into the local scope, but you may freely mutate global variables.

…

On Sun, 1 Apr 2018, 15:37 Dev Aggarwal, ***@***.***> wrote: @moses-palmer <https://github.com/moses-palmer> How are you able to modify the current varialbe from a function. AFAIK, it's not possible to modify global variable from inside a function in python without explicity declaring global in your function definition. https://stackoverflow.com/questions/4522786/modifying-a-global-variable-inside-a-function — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#20 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAjOY8x86qEFNQVWfYlYULFwBroy8Eixks5tkNgigaJpZM4MvV4j> .

[devxpy]

That explains it, thanks!

Here is a modified version that also prints a message when you release that key combination!

class MockButton:
    def __init__(self, *keys):
        self.combination = {*keys}
        self.currently_pressed = set()
        self.is_pressed = False

        listener = Listener(on_press=self._on_press, on_release=self._on_release)
        listener.start()

    def _on_press(self, key):
        if key in self.combination:
            self.currently_pressed.add(key)

        if self.currently_pressed == self.combination:
            self.is_pressed = True
            print('pressed!')

    def _on_release(self, key):
        try:
            self.currently_pressed.remove(key)

            if self.is_pressed and len(self.currently_pressed) == 0:
                self.is_pressed = False
                print('released!')

        except KeyError:
            pass


if __name__ == '__main__':
    btn = MockButton(Key.alt, Key.ctrl)
    input()

[GlassGruber]

Sorry to bump this up again, is just a question because maybe I'm misunderstanding something.
I've used your code above for this type of hotkey combination ctrl + c.
It wasn't working, so I fiddled a bit suspecting that maybe the key press wasn't fired properly, instead it was, but the key returned is not the one expected:

In [1]: from pynput import keyboard

In [2]: keyboard.Key.ctrl
Out[2]: <Key.ctrl: <17>>

In [3]: keyboard.Key.ctrl_l
Out[3]: <Key.ctrl_l: <162>>

keyboard.Key.ctrl is what I set in my script, but keyboard.Key.ctrl_l is instead what is caught by the listener; with this mismatch the condition to print the message is never met.
Am I wrong assuming that Key.ctrl should be considered a general alternative for Key.ctrl_l or Key.ctrl_r?
I'm on a Windows 7-64bit with Python 3.7

Thank you!

[moses-palmer]

You are correct in assuming that Key.ctrl is supposed to be a generic alternative to Key.ctrl_l and Key.ctrl_r.

In the case of comparisons, however, things do get a bit tricky, especially considering keycode_set_1 == keycode_set_2.

I guess a possible solution is to add a set of alternate key codes for each KeyCode instance, and override __eq__ and __hash__. In the mean time, you can use key in (Key.ctrl, Key.ctrl_l, Key.ctrl_r) when doing comparisons. That would not work for the code in @devxpy 's comment though.

[GlassGruber]

In the mean time, you can use key in (Key.ctrl, Key.ctrl_l, Key.ctrl_r) when doing comparisons. That would not work for the code in @devxpy 's comment though.

Thank you @moses-palmer, I thought so, this is the code I used if anyone needs this. As a small bonus the following code listens only to double pressing of ctrl + c in less than a second:

from pynput import keyboard
import datetime

# The key combinations to check
COMBINATIONS = [
    {keyboard.Key.ctrl_l, keyboard.KeyCode(char='c')},
    {keyboard.Key.ctrl_r, keyboard.KeyCode(char='c')}
]

# The currently active modifiers
current = set()

tnow = datetime.datetime.now()
tcounter = 0

def on_press(key):
    if any([key in comb for comb in COMBINATIONS]):
        current.add(key)
        if any(all(k in current for k in comb) for comb in COMBINATIONS):
            global tnow
            global tcounter
            tcounter += 1
            if datetime.datetime.now() - tnow < datetime.timedelta(seconds=1):
                if tcounter > 1:
                    tcounter = 0
                    main_function()
            else:
                tnow = datetime.datetime.now()
    if key == keyboard.Key.esc:
        listener.stop()


def on_release(key):
    try:
        current.remove(key)
    except KeyError:
        pass

def main_function():
    print('Main function fired!')
    # rest of your code here...

with keyboard.Listener(on_press=on_press, on_release=on_release) as listener:
    listener.join()

If you have comments on above code to improve it or any suggestions (in particular the rather sloppy global declare, I'm still learning) please let me know!

Thank you.

[gabycperezdias]

Hi @GlassGruber, I tried your code, but for some reason (I am on Windows) my "c" or "v" is like this only when pressed alone. When I have ctrl pressed, I get '\x16' '\x13' and don't match the combination.... @moses-palmer do you have any hint?

[gabycperezdias]

On a mac (changing the ctrl to cmd) I get the 'v' as '√'
@moses-palmer Is it possible that this is an issue? Or, is there a way to get the correct combination?