按下一个键时仅增加一个 [英] Increase just by one when a key is pressed

问题描述

无论我按下多长时间，我想在按下键"s"时仅将变量"shot_pressed"增加一.但是结果是变量不断增加.我按下的时间越长，变量的值越大.下面是我的代码的一部分.

I want to increase the variable "shot_pressed" just by one when the key "s" is pressed no matter how long I pressed. But the result is that the variable keeps on increasing. The longer I pressed, the bigger the value of the variable. Below is a part of my code.

import keyboard

shot_pressed = 0

if keyboard.is_pressed('s'):
    shot_pressed += 1

推荐答案

首先，您看起来像使用https://pypi.python.org/pypi/keyboard

First of all looks like you use https://pypi.python.org/pypi/keyboard

第二，我认为您的代码不像您上面编写的那样，而是像

Second, I assume your code is not like you wrote above but like

import keyboard

shot_pressed = 0

while True:
    if keyboard.is_pressed('s'):
        shot_pressed += 1
        print("shot_pressed %d times"%shot_pressed)

如果是，这是问题的核心:按下键时，is_pressed始终为True.因此 if 条件将为True，而 while 条件将重复多次.

If yes, here is the core of the problem: is_pressed will be always True, while key is pressed. So if condition will be True and while will repeat it many times.

有两种处理方法.

1)使用相同的方法，但是检查这是否是is_pressed的第一个时刻，因此引入 was_pressed 变量:

1) Use the same method, but check if this is the first is_pressed moment, so inroduce was_pressed variable:

import keyboard

shot_pressed = 0
was_pressed = False

while True:
    if keyboard.is_pressed('s'):
        if not was_pressed:
            shot_pressed += 1
            print("shot_pressed %d times"%shot_pressed)
            was_pressed = True
    else:
        was_pressed = False

2)更好地使用该库.您可以设置一个钩子，这样在按键时将调用您的函数(一次按一次).因此，代码将如下所示:

2) Better use the library. You can set a hook, so on key pressed your function will be called (only once for one press). So the code will look like this:

import keyboard

shot_pressed = 0

def on_press_reaction(event):
    global shot_pressed
    if event.name == 's':
        shot_pressed += 1
        print("shot_pressed %d times"%shot_pressed)

keyboard.on_press(on_press_reaction)

while True:
    pass

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