how to make python print into same lines all over again

Question

let me describe exactly what I'm asking. suppose that python console looks like this:

line1
line2
line3
line4
line5
...

now suppose you have a loop that prints into 3 lines with every iteration. so usually it would print into line1, line2 and line3 in the first iteration, then 4,5,6 in second and so on. I want to make it print ONLY into line1, 2 and 3, while deleting what was previously in those lines.

reason for this is I have a lot to print and what was printed before doesn't matter anymore, so this way I wouldn't create a huge number of lines.

EDIT: I think it's not a duplicate question since there are more lines in question here. I think clearing the entire console is the simplest solution here. Thanks for your answers!

Possible duplicate of [Replace console output in Python](https://stackoverflow.com/questions/6169217/replace-console-output-in-python) — custom_user, Jun 22 '17 at 09:14
Could clear the console every time the iteration happens. Thus cleaning the screen of the previous prints and making a blank slate ready for the next iteration — Goralight, Jun 22 '17 at 09:14
You could clear the console with every iteration, provided you mean you are printing to the console. This may be of use `os.system('cls')` — PeskyPotato, Jun 22 '17 at 09:15

score 1 · Answer 1 · answered Jun 22 '17 at 09:25

The best way to achieve this is to use termcap (terminal capabilities)

The curses module has what you need: https://docs.python.org/3.5/library/curses.html#module-curses

Or you can do it in a more hacky way by printing control characters and sequences directly as suggested in the other answer.

https://en.wikipedia.org/wiki/ANSI_escape_code

Eric Duminil · Answer 2 · 2017-06-22T09:21:21.463

0

Add a "\r" first to replace the last line. There shouldn't be any newline inbetween.

Python2:

>>> print("line1"),;print("\rline2")
line2

Python3:

>>> print("line1", end="");print("\rline2")
line2

"line1" has been overwritten by "\rline2".

edited Jun 22 '17 at 09:21

answered Jun 22 '17 at 09:20

Eric Duminil

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What about going back to a previous line? – Peter Wood Jun 22 '17 at 09:21
Ye this solution is not multi line. To go back to the previous line you need to move the cursor. – Maresh Jun 22 '17 at 09:27
@Maresh there is no cursor – Peter Wood Jun 22 '17 at 09:27
The terminal cursor*, it is placed after the last character that was outputted. – Maresh Jun 22 '17 at 09:29

Thierry Lathuille · Answer 3 · 2017-06-22T10:17:04.640

You can do it using ANSI escape code "\033[F", that should work in many terminals:

import time

lines = ['line %d' % n for n in range(10)]

reset_after = 3

for number, line in enumerate(lines):
    if number > 0 and not number % reset_after:
        # if we wrote n lines, we are now on line n+1,
        # so we go up n+1 lines
        print("\033[F" * (reset_after + 1))
    # We must first erase the line where we're about to write,
    # in case our new line is shorter. 
    # "\033[K" erases from the cursor
    print("\033[K" + line)
    time.sleep(0.5)

That works perfectly in my Linux terminal.

how to make python print into same lines all over again

3 Answers3