这是使用ANSI / VT100终端控制转义序列的另一种方法。
我们告诉终端仅滚动终端的上部区域,在该区域打印输出数据,以便下部区域(在该下部区域打印输入提示)保持固定。当退出程序时(使用Ctrl`` C
),我们需要恢复默认的滚动设置。
该程序首先清除屏幕,然后进入循环,提示用户输入数字n
,然后range(n)
每行打印一次中的数字,并且延迟很小,以便于查看发生的情况。每个范围的输出都从先前的范围开始。如果用户输入非整数,则将重新打印提示。该readline
模块是进口的,这样编辑和历史记录都可以在输入提示; 此模块可能并非在所有平台上都可用。
首先是Python 2版本。
''' Print text in a scrolling region of the terminal above a fixed line for input
Written by PM 2Ring 2016.05.29
Python 2 version
'''
from __future__ import print_function
from time import sleep
import readline
# Some ANSI/VT100 Terminal Control Escape Sequences
CSI = '\x1b['
CLEAR = CSI + '2J'
CLEAR_LINE = CSI + '2K'
SAVE_CURSOR = CSI + 's'
UNSAVE_CURSOR = CSI + 'u'
def emit(*args):
print(*args, sep='', end='')
def set_scroll(n):
return CSI + '0;%dr' % n
# Height of scrolling region
height = 40
GOTO_INPUT = CSI + '%d;0H' % (height + 1)
emit(CLEAR, set_scroll(height))
try:
while True:
#Get input
emit(SAVE_CURSOR, GOTO_INPUT, CLEAR_LINE)
try:
n = int(raw_input('Number: '))
except ValueError:
continue
finally:
emit(UNSAVE_CURSOR)
#Display some output
for i in range(n):
print(i)
sleep(0.1)
except KeyboardInterrupt:
#Disable scrolling, but leave cursor below the input row
emit(set_scroll(0), GOTO_INPUT, '\n')
这是在Python 2和Python 3上运行的版本。在Python 3上运行时,此脚本将调用shutil.get_terminal_size()
以设置滚动区域的高度。这 是 可能得到的终端大小在Python 2,但代码是相当混乱的,所以我选择了一个固定的高度。
我应该提到,如果在运行时更改终端大小,则此脚本的两个版本都无法很好地应对;适当的处理留给读者练习。:)
''' Print text in a scrolling region of the terminal above a fixed line for input
Written by PM 2Ring 2016.05.29
Python 2 / 3 version
'''
from __future__ import print_function
import sys
import readline
from time import sleep
if sys.version_info > (3,):
# Get the (current) number of lines in the terminal
import shutil
height = shutil.get_terminal_size().lines - 1
stdout_write_bytes = sys.stdout.buffer.write
else:
height = 40
input = raw_input
stdout_write_bytes = sys.stdout.write
# Some ANSI/VT100 Terminal Control Escape Sequences
CSI = b'\x1b['
CLEAR = CSI + b'2J'
CLEAR_LINE = CSI + b'2K'
SAVE_CURSOR = CSI + b's'
UNSAVE_CURSOR = CSI + b'u'
GOTO_INPUT = CSI + b'%d;0H' % (height + 1)
def emit(*args):
stdout_write_bytes(b''.join(args))
def set_scroll(n):
return CSI + b'0;%dr' % n
emit(CLEAR, set_scroll(height))
try:
while True:
#Get input
emit(SAVE_CURSOR, GOTO_INPUT, CLEAR_LINE)
try:
n = int(input('Number: '))
except ValueError:
continue
finally:
emit(UNSAVE_CURSOR)
#Display some output
for i in range(n):
print(i)
sleep(0.1)
except KeyboardInterrupt:
#Disable scrolling, but leave cursor below the input row
emit(set_scroll(0), GOTO_INPUT, b'\n')