Python从用户读取单个字符

时间:2009-02-04 07:08:03

标签: python input

有没有办法从用户输入中读取一个单个字符?例如,他们在终端按一个键并返回(类似于getch())。我知道Windows中有一个功能,但我想要一些跨平台的功能。

24 个答案:

答案 0 :(得分:164)

以下是指向如何在Windows,Linux和OSX中读取单个字符的网站的链接:http://code.activestate.com/recipes/134892/

class _Getch:
    """Gets a single character from standard input.  Does not echo to the
screen."""
    def __init__(self):
        try:
            self.impl = _GetchWindows()
        except ImportError:
            self.impl = _GetchUnix()

    def __call__(self): return self.impl()


class _GetchUnix:
    def __init__(self):
        import tty, sys

    def __call__(self):
        import sys, tty, termios
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch


class _GetchWindows:
    def __init__(self):
        import msvcrt

    def __call__(self):
        import msvcrt
        return msvcrt.getch()


getch = _Getch()

答案 1 :(得分:71)

sys.stdin.read(1)

基本上从STDIN读取1个字节。

如果您必须使用不等待\n的方法,您可以使用此代码,如上一个答案所示:

class _Getch:
    """Gets a single character from standard input.  Does not echo to the screen."""
    def __init__(self):
        try:
            self.impl = _GetchWindows()
        except ImportError:
            self.impl = _GetchUnix()

    def __call__(self): return self.impl()


class _GetchUnix:
    def __init__(self):
        import tty, sys

    def __call__(self):
        import sys, tty, termios
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch


class _GetchWindows:
    def __init__(self):
        import msvcrt

    def __call__(self):
        import msvcrt
        return msvcrt.getch()


getch = _Getch()

取自 http://code.activestate.com/recipes/134892/

答案 2 :(得分:59)

ActiveState recipe在两个答案中逐字引用是过度设计的。可以归结为:

def _find_getch():
    try:
        import termios
    except ImportError:
        # Non-POSIX. Return msvcrt's (Windows') getch.
        import msvcrt
        return msvcrt.getch

    # POSIX system. Create and return a getch that manipulates the tty.
    import sys, tty
    def _getch():
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(fd)
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch

    return _getch

getch = _find_getch()

答案 3 :(得分:41)

同样值得一试的是readchar库,它部分基于其他答案中提到的ActiveState配方。

安装:

pip install readchar

用法:

import readchar
print("Reading a char:")
print(repr(readchar.readchar()))
print("Reading a key:")
print(repr(readchar.readkey()))

使用Python 2.7在Windows和Linux上测试。

在Windows上,仅支持映射到字母或ASCII控制代码的键( Backspace Enter Esc Tab Ctrl + letter )。在GNU / Linux上(取决于确切的终端,也许?)你也得到插入删除 Pg Up Pg Dn < / kbd>, Home 结束 F n 键...但是,那时候,那里有&#39; s将这些特殊键与 Esc 分开的问题。

警告:与此处的大多数(所有?)答案一样,信号键如 Ctrl + C Ctrl + D捕捉并返回 Ctrl + Z (分别为'\x03''\x04''\x1a';你的程序很难中止。

答案 4 :(得分:16)

另一种方法:

import os
import sys    
import termios
import fcntl

def getch():
  fd = sys.stdin.fileno()

  oldterm = termios.tcgetattr(fd)
  newattr = termios.tcgetattr(fd)
  newattr[3] = newattr[3] & ~termios.ICANON & ~termios.ECHO
  termios.tcsetattr(fd, termios.TCSANOW, newattr)

  oldflags = fcntl.fcntl(fd, fcntl.F_GETFL)
  fcntl.fcntl(fd, fcntl.F_SETFL, oldflags | os.O_NONBLOCK)

  try:        
    while 1:            
      try:
        c = sys.stdin.read(1)
        break
      except IOError: pass
  finally:
    termios.tcsetattr(fd, termios.TCSAFLUSH, oldterm)
    fcntl.fcntl(fd, fcntl.F_SETFL, oldflags)
  return c

来自this blog post

答案 5 :(得分:12)

我认为此时非常笨重,在不同平台上进行调试非常麻烦。

你最好使用像pyglet,pygame,cocos2d这样的东西 - 如果你做的比这更精细,需要视觉效果,或者诅咒如果你打算使用终端

诅咒是标准的:http://docs.python.org/library/curses.html

答案 6 :(得分:8)

此代码基于here,如果 Ctrl + C Ctrl + D 被按下。

应该适用于Windows和Linux。 OS X版本可从原始源获得。

class _Getch:
    """Gets a single character from standard input.  Does not echo to the screen."""
    def __init__(self):
        try:
            self.impl = _GetchWindows()
        except ImportError:
            self.impl = _GetchUnix()

    def __call__(self): 
        char = self.impl()
        if char == '\x03':
            raise KeyboardInterrupt
        elif char == '\x04':
            raise EOFError
        return char

class _GetchUnix:
    def __init__(self):
        import tty
        import sys

    def __call__(self):
        import sys
        import tty
        import termios
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch


class _GetchWindows:
    def __init__(self):
        import msvcrt

    def __call__(self):
        import msvcrt
        return msvcrt.getch()


getch = _Getch()

答案 7 :(得分:7)

(当前)排名靠前的答案(使用ActiveState代码)过于复杂。当一个单纯的功能足够时,我没有看到使用类的理由。下面是两个完成相同但具有更多可读代码的实现。

这两种实施方式都是:

  1. 在Python 2或Python 3中工作得很好
  2. 适用于Windows,OSX和Linux
  3. 只读取一个字节(即,他们不等待换行符)
  4. 不依赖任何外部库
  5. 是自包含的(函数定义之外没有代码)
  6. 版本1:可读且简单

    def getChar():
        try:
            # for Windows-based systems
            import msvcrt # If successful, we are on Windows
            return msvcrt.getch()
    
        except ImportError:
            # for POSIX-based systems (with termios & tty support)
            import tty, sys, termios  # raises ImportError if unsupported
    
            fd = sys.stdin.fileno()
            oldSettings = termios.tcgetattr(fd)
    
            try:
                tty.setcbreak(fd)
                answer = sys.stdin.read(1)
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, oldSettings)
    
            return answer
    

    版本2:避免重复导入和异常处理:

    [编辑] 我错过了ActiveState代码的一个优势。如果您计划多次读取字符,那么该代码可以避免在类Unix系统上重复Windows导入和ImportError异常处理的成本(可忽略不计)。虽然您可能应该更关注代码可读性而不是可忽略的优化,但这里有一个替代方案(类似于Louis的答案,但getChar()是自包含的),其功能与ActiveState代码相同,并且更具可读性:< / p>

    def getChar():
        # figure out which function to use once, and store it in _func
        if "_func" not in getChar.__dict__:
            try:
                # for Windows-based systems
                import msvcrt # If successful, we are on Windows
                getChar._func=msvcrt.getch
    
            except ImportError:
                # for POSIX-based systems (with termios & tty support)
                import tty, sys, termios # raises ImportError if unsupported
    
                def _ttyRead():
                    fd = sys.stdin.fileno()
                    oldSettings = termios.tcgetattr(fd)
    
                    try:
                        tty.setcbreak(fd)
                        answer = sys.stdin.read(1)
                    finally:
                        termios.tcsetattr(fd, termios.TCSADRAIN, oldSettings)
    
                    return answer
    
                getChar._func=_ttyRead
    
        return getChar._func()
    

    执行上述任一getChar()版本的示例代码:

    from __future__ import print_function # put at top of file if using Python 2
    
    # Example of a prompt for one character of input
    promptStr   = "Please give me a character:"
    responseStr = "Thank you for giving me a '{}'."
    print(promptStr, end="\n> ")
    answer = getChar()
    print("\n")
    print(responseStr.format(answer))
    

答案 8 :(得分:4)

答案here提供了丰富的信息,但我还想要一种方法来异步获取按键,并在单独的事件中触发按键,所有操作都采用线程安全的跨平台方式。 PyGame对我来说也太臃肿了。所以我做了以下(在Python 2.7中,但我怀疑它很容易移植),我想我会在这里分享,以防它对其他人有用。我将其存储在名为keyPress.py的文件中。

class _Getch:
    """Gets a single character from standard input.  Does not echo to the
screen. From http://code.activestate.com/recipes/134892/"""
    def __init__(self):
        try:
            self.impl = _GetchWindows()
        except ImportError:
            try:
                self.impl = _GetchMacCarbon()
            except(AttributeError, ImportError):
                self.impl = _GetchUnix()

    def __call__(self): return self.impl()


class _GetchUnix:
    def __init__(self):
        import tty, sys, termios # import termios now or else you'll get the Unix version on the Mac

    def __call__(self):
        import sys, tty, termios
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch

class _GetchWindows:
    def __init__(self):
        import msvcrt

    def __call__(self):
        import msvcrt
        return msvcrt.getch()

class _GetchMacCarbon:
    """
    A function which returns the current ASCII key that is down;
    if no ASCII key is down, the null string is returned.  The
    page http://www.mactech.com/macintosh-c/chap02-1.html was
    very helpful in figuring out how to do this.
    """
    def __init__(self):
        import Carbon
        Carbon.Evt #see if it has this (in Unix, it doesn't)

    def __call__(self):
        import Carbon
        if Carbon.Evt.EventAvail(0x0008)[0]==0: # 0x0008 is the keyDownMask
            return ''
        else:
            #
            # The event contains the following info:
            # (what,msg,when,where,mod)=Carbon.Evt.GetNextEvent(0x0008)[1]
            #
            # The message (msg) contains the ASCII char which is
            # extracted with the 0x000000FF charCodeMask; this
            # number is converted to an ASCII character with chr() and
            # returned
            #
            (what,msg,when,where,mod)=Carbon.Evt.GetNextEvent(0x0008)[1]
            return chr(msg & 0x000000FF)

import threading


# From  https://stackoverflow.com/a/2022629/2924421
class Event(list):
    def __call__(self, *args, **kwargs):
        for f in self:
            f(*args, **kwargs)

    def __repr__(self):
        return "Event(%s)" % list.__repr__(self)            


def getKey():
    inkey = _Getch()
    import sys
    for i in xrange(sys.maxint):
        k=inkey()
        if k<>'':break
    return k

class KeyCallbackFunction():
    callbackParam = None
    actualFunction = None

    def __init__(self, actualFunction, callbackParam):
        self.actualFunction = actualFunction
        self.callbackParam = callbackParam

    def doCallback(self, inputKey):
        if not self.actualFunction is None:
            if self.callbackParam is None:
                callbackFunctionThread = threading.Thread(target=self.actualFunction, args=(inputKey,))
            else:
                callbackFunctionThread = threading.Thread(target=self.actualFunction, args=(inputKey,self.callbackParam))

            callbackFunctionThread.daemon = True
            callbackFunctionThread.start()



class KeyCapture():


    gotKeyLock = threading.Lock()
    gotKeys = []
    gotKeyEvent = threading.Event()

    keyBlockingSetKeyLock = threading.Lock()

    addingEventsLock = threading.Lock()
    keyReceiveEvents = Event()


    keysGotLock = threading.Lock()
    keysGot = []

    keyBlockingKeyLockLossy = threading.Lock()
    keyBlockingKeyLossy = None
    keyBlockingEventLossy = threading.Event()

    keysBlockingGotLock = threading.Lock()
    keysBlockingGot = []
    keyBlockingGotEvent = threading.Event()



    wantToStopLock = threading.Lock()
    wantToStop = False

    stoppedLock = threading.Lock()
    stopped = True

    isRunningEvent = False

    getKeyThread = None

    keyFunction = None
    keyArgs = None

    # Begin capturing keys. A seperate thread is launched that
    # captures key presses, and then these can be received via get,
    # getAsync, and adding an event via addEvent. Note that this
    # will prevent the system to accept keys as normal (say, if
    # you are in a python shell) because it overrides that key
    # capturing behavior.

    # If you start capture when it's already been started, a
    # InterruptedError("Keys are still being captured")
    # will be thrown

    # Note that get(), getAsync() and events are independent, so if a key is pressed:
    #
    # 1: Any calls to get() that are waiting, with lossy on, will return
    #    that key
    # 2: It will be stored in the queue of get keys, so that get() with lossy
    #    off will return the oldest key pressed not returned by get() yet.
    # 3: All events will be fired with that key as their input
    # 4: It will be stored in the list of getAsync() keys, where that list
    #    will be returned and set to empty list on the next call to getAsync().
    # get() call with it, aand add it to the getAsync() list.
    def startCapture(self, keyFunction=None, args=None):
        # Make sure we aren't already capturing keys
        self.stoppedLock.acquire()
        if not self.stopped:
            self.stoppedLock.release()
            raise InterruptedError("Keys are still being captured")
            return
        self.stopped = False
        self.stoppedLock.release()

        # If we have captured before, we need to allow the get() calls to actually
        # wait for key presses now by clearing the event
        if self.keyBlockingEventLossy.is_set():
            self.keyBlockingEventLossy.clear()

        # Have one function that we call every time a key is captured, intended for stopping capture
        # as desired
        self.keyFunction = keyFunction
        self.keyArgs = args

        # Begin capturing keys (in a seperate thread)
        self.getKeyThread = threading.Thread(target=self._threadProcessKeyPresses)
        self.getKeyThread.daemon = True
        self.getKeyThread.start()

        # Process key captures (in a seperate thread)
        self.getKeyThread = threading.Thread(target=self._threadStoreKeyPresses)
        self.getKeyThread.daemon = True
        self.getKeyThread.start()


    def capturing(self):
        self.stoppedLock.acquire()
        isCapturing = not self.stopped
        self.stoppedLock.release()
        return isCapturing
    # Stops the thread that is capturing keys on the first opporunity
    # has to do so. It usually can't stop immediately because getting a key
    # is a blocking process, so this will probably stop capturing after the
    # next key is pressed.
    #
    # However, Sometimes if you call stopCapture it will stop before starting capturing the
    # next key, due to multithreading race conditions. So if you want to stop capturing
    # reliably, call stopCapture in a function added via addEvent. Then you are
    # guaranteed that capturing will stop immediately after the rest of the callback
    # functions are called (before starting to capture the next key).
    def stopCapture(self):
        self.wantToStopLock.acquire()
        self.wantToStop = True 
        self.wantToStopLock.release()

    # Takes in a function that will be called every time a key is pressed (with that
    # key passed in as the first paramater in that function)
    def addEvent(self, keyPressEventFunction, args=None):   
        self.addingEventsLock.acquire()
        callbackHolder = KeyCallbackFunction(keyPressEventFunction, args)
        self.keyReceiveEvents.append(callbackHolder.doCallback)
        self.addingEventsLock.release()
    def clearEvents(self):
        self.addingEventsLock.acquire()
        self.keyReceiveEvents = Event()
        self.addingEventsLock.release()
    # Gets a key captured by this KeyCapture, blocking until a key is pressed.
    # There is an optional lossy paramater:
    # If True all keys before this call are ignored, and the next pressed key
    #   will be returned.
    # If False this will return the oldest key captured that hasn't
    #   been returned by get yet. False is the default.
    def get(self, lossy=False):
        if lossy:
            # Wait for the next key to be pressed
            self.keyBlockingEventLossy.wait()
            self.keyBlockingKeyLockLossy.acquire()
            keyReceived = self.keyBlockingKeyLossy
            self.keyBlockingKeyLockLossy.release()
            return keyReceived
        else:
            while True:
                # Wait until a key is pressed
                self.keyBlockingGotEvent.wait()

                # Get the key pressed
                readKey = None
                self.keysBlockingGotLock.acquire()
                # Get a key if it exists
                if len(self.keysBlockingGot) != 0:
                    readKey = self.keysBlockingGot.pop(0)
                # If we got the last one, tell us to wait
                if len(self.keysBlockingGot) == 0:
                    self.keyBlockingGotEvent.clear()
                self.keysBlockingGotLock.release()

                # Process the key (if it actually exists)
                if not readKey is None:
                    return readKey

                # Exit if we are stopping
                self.wantToStopLock.acquire()
                if self.wantToStop:
                    self.wantToStopLock.release()
                    return None
                self.wantToStopLock.release()




    def clearGetList(self):
        self.keysBlockingGotLock.acquire()
        self.keysBlockingGot = []
        self.keysBlockingGotLock.release()

    # Gets a list of all keys pressed since the last call to getAsync, in order
    # from first pressed, second pressed, .., most recent pressed
    def getAsync(self):
        self.keysGotLock.acquire();
        keysPressedList = list(self.keysGot)
        self.keysGot = []
        self.keysGotLock.release()
        return keysPressedList

    def clearAsyncList(self):
        self.keysGotLock.acquire();
        self.keysGot = []
        self.keysGotLock.release();

    def _processKey(self, readKey):
        # Append to list for GetKeyAsync
        self.keysGotLock.acquire()
        self.keysGot.append(readKey)
        self.keysGotLock.release()

        # Call lossy blocking key events
        self.keyBlockingKeyLockLossy.acquire()
        self.keyBlockingKeyLossy = readKey
        self.keyBlockingEventLossy.set()
        self.keyBlockingEventLossy.clear()
        self.keyBlockingKeyLockLossy.release()

        # Call non-lossy blocking key events
        self.keysBlockingGotLock.acquire()
        self.keysBlockingGot.append(readKey)
        if len(self.keysBlockingGot) == 1:
            self.keyBlockingGotEvent.set()
        self.keysBlockingGotLock.release()

        # Call events added by AddEvent
        self.addingEventsLock.acquire()
        self.keyReceiveEvents(readKey)
        self.addingEventsLock.release()

    def _threadProcessKeyPresses(self):
        while True:
            # Wait until a key is pressed
            self.gotKeyEvent.wait()

            # Get the key pressed
            readKey = None
            self.gotKeyLock.acquire()
            # Get a key if it exists
            if len(self.gotKeys) != 0:
                readKey = self.gotKeys.pop(0)
            # If we got the last one, tell us to wait
            if len(self.gotKeys) == 0:
                self.gotKeyEvent.clear()
            self.gotKeyLock.release()

            # Process the key (if it actually exists)
            if not readKey is None:
                self._processKey(readKey)

            # Exit if we are stopping
            self.wantToStopLock.acquire()
            if self.wantToStop:
                self.wantToStopLock.release()
                break
            self.wantToStopLock.release()

    def _threadStoreKeyPresses(self):
        while True:
            # Get a key
            readKey = getKey()

            # Run the potential shut down function
            if not self.keyFunction is None:
                self.keyFunction(readKey, self.keyArgs)

            # Add the key to the list of pressed keys
            self.gotKeyLock.acquire()
            self.gotKeys.append(readKey)
            if len(self.gotKeys) == 1:
                self.gotKeyEvent.set()
            self.gotKeyLock.release()

            # Exit if we are stopping
            self.wantToStopLock.acquire()
            if self.wantToStop:
                self.wantToStopLock.release()
                self.gotKeyEvent.set()
                break
            self.wantToStopLock.release()


        # If we have reached here we stopped capturing

        # All we need to do to clean up is ensure that
        # all the calls to .get() now return None.
        # To ensure no calls are stuck never returning,
        # we will leave the event set so any tasks waiting
        # for it immediately exit. This will be unset upon
        # starting key capturing again.

        self.stoppedLock.acquire()

        # We also need to set this to True so we can start up
        # capturing again.
        self.stopped = True
        self.stopped = True

        self.keyBlockingKeyLockLossy.acquire()
        self.keyBlockingKeyLossy = None
        self.keyBlockingEventLossy.set()
        self.keyBlockingKeyLockLossy.release()

        self.keysBlockingGotLock.acquire()
        self.keyBlockingGotEvent.set()
        self.keysBlockingGotLock.release()

        self.stoppedLock.release()

这个想法是你可以简单地调用keyPress.getKey(),它将从键盘读取一个键,然后返回它。

如果你想要更多的东西,我做了一个KeyCapture对象。您可以通过keys = keyPress.KeyCapture()

之类的内容创建一个

然后你可以做三件事:

addEvent(functionName)接受任何接受一个参数的函数。然后每次按下一个键时,将使用该键的字符串调用此函数作为其输入。它们在一个单独的线程中运行,因此您可以阻止它们中的所有内容,它不会破坏KeyCapturer的功能,也不会延迟其他事件。

get()以与之前相同的阻止方式返回密钥。现在需要它,因为现在通过KeyCapture对象捕获密钥,因此keyPress.getKey()将与该行为冲突,并且它们都会丢失一些密钥,因为一次只能捕获一个密钥。另外,假设用户按'a',然后按'b',则调用get(),用户按'c'。 get()调用将立即返回'a',然后如果再次调用它将返回'b',然后返回'c'。如果再次调用它,它将阻塞,直到按下另一个键。这样可确保您不会错过任何键,如果需要,可以阻止。因此,这与

之前的keyPress.getKey()略有不同

如果您想要getKey()的行为,get(lossy=True)就像get(),除了它只会在调用{{1}之后返回按键的键}}。因此,在上面的示例中,get()将阻塞,直到用户按下“c”,然后如果再次调用它,它将阻塞,直到按下另一个键。

get()有点不同。它专为需要进行大量处理的东西而设计,然后偶尔返回并检查按下了哪些键。因此,getAsync()返回自上次调用getAsync()以来按下的所有键的列表,按照从按下的最旧键到按下的最新键的顺序。它也不会阻止,这意味着如果自上次调用getAsync()后没有按下任何键,则会返回空的getAsync()

要真正开始捕获密钥,您需要使用上面提到的[]对象来呼叫keys.startCapture()keys是非阻塞的,只需启动一个只记录按键的线程,另一个线程来处理这些按键。有两个线程可以确保记录按键的线程不会错过任何键。

如果您想要停止捕获密钥,可以调用startCapture,它将停止捕获密钥。但是,由于捕获密钥是阻塞操作,因此线程捕获密钥可能在调用keys.stopCapture()后再捕获一个密钥。

为了防止这种情况,你可以将一个可选参数传递给一个函数的stopCapture(),它只是检查一个键是否等于'c'然后退出。重要的是这个功能之前做的很少,例如,这里的睡眠会导致我们错过按键。

但是,如果在此函数中调用startCapture(functionName, args),则会立即停止键捕获,而不再尝试捕获,并且将立即返回所有stopCapture()调用,如果没有键,则返回None已经被压了。

此外,由于get()get()存储了所有先前按下的键(直到您检索它们),您可以调用getAsync()clearGetList()来忘记之前按下的键

请注意clearAsyncList()get()和事件是独立的,因此如果按下某个键: 1.对getAsync()的一个正在等待的电话将会返回    那把钥匙。其他等待的电话(如果有的话)将继续等待。 2.该密钥将存储在获取密钥的队列中,因此具有有损关闭的get()将返回[{1}}尚未返回的最旧密钥。 3.所有事件都将以该密钥作为输入触发 4.该密钥将存储在get()密钥列表中,其中lis twill返回并在下次调用get()时设置为空列表

如果所有这些都太多,这是一个示例用例:

getAsync()

从我所做的简单测试来看,它对我来说效果很好,但如果我错过了一些东西,我也很乐意接受别人的反馈。

我也发布了此here

答案 9 :(得分:4)

这可能是上下文管理器的用例。暂且不考虑Windows操作系统的限制,这是我的建议:

#!/usr/bin/env python3
# file: 'readchar.py'
"""
Implementation of a way to get a single character of input
without waiting for the user to hit <Enter>.
(OS is Linux, Ubuntu 14.04)
"""

import tty, sys, termios

class ReadChar():
    def __enter__(self):
        self.fd = sys.stdin.fileno()
        self.old_settings = termios.tcgetattr(self.fd)
        tty.setraw(sys.stdin.fileno())
        return sys.stdin.read(1)
    def __exit__(self, type, value, traceback):
        termios.tcsetattr(self.fd, termios.TCSADRAIN, self.old_settings)

def test():
    while True:
        with ReadChar() as rc:
            char = rc
        if ord(char) <= 32:
            print("You entered character with ordinal {}."\
                        .format(ord(char)))
        else:
            print("You entered character '{}'."\
                        .format(char))
        if char in "^C^D":
            sys.exit()

if __name__ == "__main__":
    test()

答案 10 :(得分:3)

尝试使用此功能:http://home.wlu.edu/~levys/software/kbhit.py 它是非阻塞的(这意味着你可以有一个while循环并检测按键而不会停止它)和跨平台。

import os

# Windows
if os.name == 'nt':
    import msvcrt

# Posix (Linux, OS X)
else:
    import sys
    import termios
    import atexit
    from select import select


class KBHit:

    def __init__(self):
        '''Creates a KBHit object that you can call to do various keyboard things.'''

        if os.name == 'nt':
            pass

        else:

            # Save the terminal settings
            self.fd = sys.stdin.fileno()
            self.new_term = termios.tcgetattr(self.fd)
            self.old_term = termios.tcgetattr(self.fd)

            # New terminal setting unbuffered
            self.new_term[3] = (self.new_term[3] & ~termios.ICANON & ~termios.ECHO)
            termios.tcsetattr(self.fd, termios.TCSAFLUSH, self.new_term)

            # Support normal-terminal reset at exit
            atexit.register(self.set_normal_term)


    def set_normal_term(self):
        ''' Resets to normal terminal.  On Windows this is a no-op.
        '''

        if os.name == 'nt':
            pass

        else:
            termios.tcsetattr(self.fd, termios.TCSAFLUSH, self.old_term)


    def getch(self):
        ''' Returns a keyboard character after kbhit() has been called.
            Should not be called in the same program as getarrow().
        '''

        s = ''

        if os.name == 'nt':
            return msvcrt.getch().decode('utf-8')

        else:
            return sys.stdin.read(1)


    def getarrow(self):
        ''' Returns an arrow-key code after kbhit() has been called. Codes are
        0 : up
        1 : right
        2 : down
        3 : left
        Should not be called in the same program as getch().
        '''

        if os.name == 'nt':
            msvcrt.getch() # skip 0xE0
            c = msvcrt.getch()
            vals = [72, 77, 80, 75]

        else:
            c = sys.stdin.read(3)[2]
            vals = [65, 67, 66, 68]

        return vals.index(ord(c.decode('utf-8')))


    def kbhit(self):
        ''' Returns True if keyboard character was hit, False otherwise.
        '''
        if os.name == 'nt':
            return msvcrt.kbhit()

        else:
            dr,dw,de = select([sys.stdin], [], [], 0)
            return dr != []

使用此示例:

import kbhit

kb = kbhit.KBHit()

while(True): 
    print("Key not pressed") #Do something
    if kb.kbhit(): #If a key is pressed:
        k_in = kb.getch() #Detect what key was pressed
        print("You pressed ", k_in, "!") #Do something
kb.set_normal_term()

或者您可以使用getch module from PyPi。但这会阻止while循环

答案 11 :(得分:3)

这是非阻塞,读取密钥并将其存储在keypress.key中。

import Tkinter as tk


class Keypress:
    def __init__(self):
        self.root = tk.Tk()
        self.root.geometry('300x200')
        self.root.bind('<KeyPress>', self.onKeyPress)

    def onKeyPress(self, event):
        self.key = event.char

    def __eq__(self, other):
        return self.key == other

    def __str__(self):
        return self.key

在你的程序中

keypress = Keypress()

while something:
   do something
   if keypress == 'c':
        break
   elif keypress == 'i': 
       print('info')
   else:
       print("i dont understand %s" % keypress)

答案 12 :(得分:3)

其他一个答案中的评论提到了cbreak模式,这对Unix实现很重要,因为你通常不希望^ c(KeyboardError)被getchar使用(就像你在使用它时一样)将终端设置为原始模式,正如大多数其他答案所做的那样。)

另一个重要的细节是,如果您正在寻找一个字符而不是一个字节,您应该从输入流中读取4个字节,因为#39; s单个字符在UTF-8(Python 3+)中包含的最大字节数。只读取一个字节会对多字节字符(例如键盘箭头)产生意外结果。

这是我改变的Unix实现:

import contextlib
import os
import sys
import termios
import tty


_MAX_CHARACTER_BYTE_LENGTH = 4


@contextlib.contextmanager
def _tty_reset(file_descriptor):
    """
    A context manager that saves the tty flags of a file descriptor upon
    entering and restores them upon exiting.
    """
    old_settings = termios.tcgetattr(file_descriptor)
    try:
        yield
    finally:
        termios.tcsetattr(file_descriptor, termios.TCSADRAIN, old_settings)


def get_character(file=sys.stdin):
    """
    Read a single character from the given input stream (defaults to sys.stdin).
    """
    file_descriptor = file.fileno()
    with _tty_reset(file_descriptor):
        tty.setcbreak(file_descriptor)
        return os.read(file_descriptor, _MAX_CHARACTER_BYTE_LENGTH)

答案 13 :(得分:2)

尝试使用pygame:

import pygame
pygame.init()             // eliminate error, pygame.error: video system not initialized
keys = pygame.key.get_pressed()

if keys[pygame.K_SPACE]:
    d = "space key"

print "You pressed the", d, "."

答案 14 :(得分:1)

python中的curses包可用于输入“原始”模式,只需几个语句即可从终端输入字符。 Curses的主要用途是接管屏幕输出,这可能不是你想要的。此代码段使用print()语句,这些语句可用,但您必须了解curses如何更改附加到输出的行结尾。

#!/usr/bin/python3
# Demo of single char terminal input in raw mode with the curses package.
import sys, curses

def run_one_char(dummy):
    'Run until a carriage return is entered'
    char = ' '
    print('Welcome to curses', flush=True)
    while ord(char) != 13:
        char = one_char()

def one_char():
    'Read one character from the keyboard'
    print('\r? ', flush= True, end = '')

    ## A blocking single char read in raw mode. 
    char = sys.stdin.read(1)
    print('You entered %s\r' % char)
    return char

## Must init curses before calling any functions
curses.initscr()
## To make sure the terminal returns to its initial settings,
## and to set raw mode and guarantee cleanup on exit. 
curses.wrapper(run_one_char)
print('Curses be gone!')

答案 15 :(得分:1)

ActiveState的配方似乎包含了#34; posix&#34;阻止Ctrl-C中断的系统(我使用的是Mac)。如果我在我的脚本中放入以下代码:

while(True):
    print(getch())

我永远无法用Ctrl-C终止脚本,我必须杀死我的终端才能逃脱。

我认为以下几行是原因,而且它也太残酷了:

tty.setraw(sys.stdin.fileno())

除此之外,并不真正需要包ttytermios足以处理它。

以下是适用于我的改进代码(Ctrl-C将中断),以及在您键入时回显char的额外getche函数:

if sys.platform == 'win32':
    import msvcrt
    getch = msvcrt.getch
    getche = msvcrt.getche
else:
    import sys
    import termios
    def __gen_ch_getter(echo):
        def __fun():
            fd = sys.stdin.fileno()
            oldattr = termios.tcgetattr(fd)
            newattr = oldattr[:]
            try:
                if echo:
                    # disable ctrl character printing, otherwise, backspace will be printed as "^?"
                    lflag = ~(termios.ICANON | termios.ECHOCTL)
                else:
                    lflag = ~(termios.ICANON | termios.ECHO)
                newattr[3] &= lflag
                termios.tcsetattr(fd, termios.TCSADRAIN, newattr)
                ch = sys.stdin.read(1)
                if echo and ord(ch) == 127: # backspace
                    # emulate backspace erasing
                    # https://stackoverflow.com/a/47962872/404271
                    sys.stdout.write('\b \b')
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, oldattr)
            return ch
        return __fun
    getch = __gen_ch_getter(False)
    getche = __gen_ch_getter(True)

参考文献:

答案 16 :(得分:0)

内置raw_input应该有所帮助。

for i in range(3):
    print ("So much work to do!")
k = raw_input("Press any key to continue...")
print ("Ok, back to work.")

答案 17 :(得分:0)

我对python3的解决方案,不依赖于任何pip包。

# precondition: import tty, sys
def query_yes_no(question, default=True):
    """
    Ask the user a yes/no question.
    Returns immediately upon reading one-char answer.
    Accepts multiple language characters for yes/no.
    """
    if not sys.stdin.isatty():
        return default
    if default:
        prompt = "[Y/n]?"
        other_answers = "n"
    else:
        prompt = "[y/N]?"
        other_answers = "yjosiá"

    print(question,prompt,flush= True,end=" ")
    oldttysettings = tty.tcgetattr(sys.stdin.fileno())
    try:
        tty.setraw(sys.stdin.fileno())
        return not sys.stdin.read(1).lower() in other_answers
    except:
        return default
    finally:
        tty.tcsetattr(sys.stdin.fileno(), tty.TCSADRAIN , oldttysettings)
        sys.stdout.write("\r\n")
        tty.tcdrain(sys.stdin.fileno())

答案 18 :(得分:0)

我相信这是最优雅的解决方案之一。

import os

if os.name == 'nt':
    import msvcrt
    def getch():
        return msvcrt.getch().decode()
else:
    import sys, tty, termios
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    def getch():
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch

然后在代码中使用它:

if getch() == chr(ESC_ASCII_VALUE):
    print("ESC!")

答案 19 :(得分:0)

如果我正在做复杂的事情,我将使用诅咒来读取键。但是很多时候,我只想要一个简单的Python 3脚本,该脚本使用标准库并且可以读取箭头键,因此我可以这样做:

import sys, termios, tty

key_Enter = 13
key_Esc = 27
key_Up = '\033[A'
key_Dn = '\033[B'
key_Rt = '\033[C'
key_Lt = '\033[D'

fdInput = sys.stdin.fileno()
termAttr = termios.tcgetattr(0)

def getch():
    tty.setraw(fdInput)
    ch = sys.stdin.buffer.raw.read(4).decode(sys.stdin.encoding)
    if len(ch) == 1:
        if ord(ch) < 32 or ord(ch) > 126:
            ch = ord(ch)
    elif ord(ch[0]) == 27:
        ch = '\033' + ch[1:]
    termios.tcsetattr(fdInput, termios.TCSADRAIN, termAttr)
    return ch

答案 20 :(得分:0)

被接受的答案对我而言效果不佳(我按住一个键,什么也不会发生,然后我再按另一个键就可以了。)

了解了 curses 模块后,这似乎确实是正确的方法。现在它可以通过windows-cursors用于Windows(可通过pip获得),因此您可以以与平台无关的方式进行编程。这是一个受nice tutorial在YouTube上启发的示例:

import curses                                                                                                                                       
def getkey(stdscr):
    curses.curs_set(0)
    while True:
        key = stdscr.getch()
        if key != -1:
            break
    return key

if __name__ == "__main__":
    print(curses.wrapper(getkey))

使用.py扩展名保存它,或在交互模式下运行curses.wrapper(getkey)

答案 21 :(得分:0)

在这里回答:raw_input in python without pressing enter

使用此代码-

from tkinter import Tk, Frame


def __set_key(e, root):
    """
    e - event with attribute 'char', the released key
    """
    global key_pressed
    if e.char:
        key_pressed = e.char
        root.destroy()


def get_key(msg="Press any key ...", time_to_sleep=3):
    """
    msg - set to empty string if you don't want to print anything
    time_to_sleep - default 3 seconds
    """
    global key_pressed
    if msg:
        print(msg)
    key_pressed = None
    root = Tk()
    root.overrideredirect(True)
    frame = Frame(root, width=0, height=0)
    frame.bind("<KeyRelease>", lambda f: __set_key(f, root))
    frame.pack()
    root.focus_set()
    frame.focus_set()
    frame.focus_force()  # doesn't work in a while loop without it
    root.after(time_to_sleep * 1000, func=root.destroy)
    root.mainloop()
    root = None  # just in case
    return key_pressed


def __main():
        c = None
        while not c:
                c = get_key("Choose your weapon ... ", 2)
        print(c)

if __name__ == "__main__":
    __main()

参考:https://github.com/unfor19/mg-tools/blob/master/mgtools/get_key_pressed.py

答案 22 :(得分:0)

如果您只想注册一个按键,即使用户多次按下该按键或保持按键按下时间更长。 为了避免多次按下输入,请使用while循环并将其传递。

import keyboard

while(True):
  if(keyboard.is_pressed('w')):
      s+=1
      while(keyboard.is_pressed('w')):
        pass
  if(keyboard.is_pressed('s')):
      s-=1
      while(keyboard.is_pressed('s')):
        pass
  print(s)

答案 23 :(得分:0)

如果您只想按住屏幕,这样就可以在终端上看到结果,只需写

input()

在代码末尾,它将保持屏幕显示