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
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
其他回答
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())
python中的curses包可以使用一些语句从终端进入“原始”模式进行字符输入。Curses的主要用途是接管屏幕进行输出,这可能不是你想要的。此代码片段使用print()语句代替,这是可用的,但必须注意curses如何更改附加到输出的行结束符。
#!/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!')
如果你只是想按住屏幕,这样你就可以在终端上看到结果
input()
在代码的末尾,它将保存屏幕
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
摘自这篇博文。
我相信这是一个最优雅的解决方案。
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!")
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