如何动态刷新多行output

Question

I want to refresh some info dynamically(just like progress bar), I can do it with following code

#! /usr/bin/env python
import sys
import time

print "start the output"
def loop():
    i = 0

    while 1:
        i += 1
        output = "\rFirst_line%s..." % str(i) 
        sys.stdout.write(output)        
        sys.stdout.flush()
        time.sleep(1)
loop()

It could only output single_line info dynamically, When add '\n' into output, It couldn't work as expect.

output = "\rFirst_line%s...\n" % str(i)

Any way could help it to refresh multi_line content?

Answer 1

I also had that situation, and I finally got a idea to solve this ;D

reprint- A simple module for Python 2/3 to print and refresh multi line output contents in terminal

You can simply treat that output instance as a normal dict or list (depend on which mode you use). When you modify that content in the output instance, the output in terminal will automatically refresh :D

Here is a example:

from reprint import output
import time
import random

print "start the output"

with output(initial_len=3, interval=0) as output_lines:
    while True:
        output_lines[0] = "First_line  {}...".format(random.randint(1,10))
        output_lines[1] = "Second_line {}...".format(random.randint(1,10))
        output_lines[2] = "Third_line  {}...".format(random.randint(1,10))
        time.sleep(0.5)

Answer 2

你可以用诅咒来做，但这是非常重要的。

Answer 3

There is no way to do that system-independently (when saying "system" I mean not just OS, but also terminal app and its setup as well) since there is no standard escape sequence that would move cursor up. As for system-dependent ways, they may exist for your configuration, but more information about your system is needed. And anyway, usually it is not a good idea to use such features.

PS Hope you are not going to redirect your program's output to a file. If redirected to a file, such progress indicators produce terrible output.

Answer 4

Simply do:

import time
import random

while True:
    print(f'''First Line {random.randint(1,10)}
Second Line {random.randint(1,10)}        
Third Line  {random.randint(1,10)}''')
    sys.stdout.write("\x1b[1A"*3) # Cursor up 3 lines
    time.sleep(0.5)

Answer 5

write '\\b' to the console:

import sys
import time

print "start the output"
def loop():
    i = 0
    output = "\rFirst_line%s..." % str(0) 
    sys.stdout.write(output)
    while 1:
        sys.stdout.write('\b'*len(output))
        i += 1
        output = "\rFirst_line%s..." % str(i) 
        sys.stdout.write(output)        
        sys.stdout.flush()
        time.sleep(1)
loop()