是否有办法从用户输入中读取单个字符?例如,他们在终端上按下一个键,它就会返回(有点像getch())。我知道Windows中有这个功能,但我想要跨平台的东西。
当前回答
sys.stdin.read(1)
基本上会从STDIN读取1个字节。
如果你必须使用不等待\n的方法,你可以按照之前的回答使用这段代码:
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()
(摘自http://code.activestate.com/recipes/134892/)
其他回答
下面是ActiveState Recipes网站的链接,告诉你如何在Windows、Linux和OSX中读取单个字符:
getch()-类似于在Windows和Unix上从stdin读取的非缓冲字符
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()
这可能是上下文管理器的一个用例。不考虑Windows操作系统,以下是我的建议:
#!/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()
sys.stdin.read(1)
基本上会从STDIN读取1个字节。
如果你必须使用不等待\n的方法,你可以按照之前的回答使用这段代码:
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()
(摘自http://code.activestate.com/recipes/134892/)
试试这个:http://home.wlu.edu/~levys/software/kbhit.py 它是非阻塞的(这意味着您可以有一个while循环并检测按键而无需停止它)和跨平台的。
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 != []
使用这个的例子:
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PyPi中的getch模块。但是这会阻塞while循环
ActiveState的配方似乎包含一个小错误,“posix”系统,防止Ctrl-C中断(我使用Mac)。如果我把下面的代码放在我的脚本:
while(True):
print(getch())
我将永远无法用Ctrl-C终止脚本,我必须杀死我的终端才能退出。
我认为下面这句话是原因,而且它也太残酷了:
tty.setraw(sys.stdin.fileno())
除此之外,tty包实际上并不需要,termios就足以处理它了。
下面是改进的代码,为我工作(Ctrl-C将中断),与额外的getche函数,当你输入的字符回显:
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)
引用:
https://pypi.python.org/pypi/getch
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