How can I print over the current line in a command

Question

On Unix, I can either use \r (carriage return) or \b (backspace) to print over text already visible in the shell (i.e. overwrite the current line again).

Can I achieve the same effect in a Windows command line from a Python script?

I tried the curses module but it doesn't seem to be available on Windows.

Answer 1

yes:

import sys
import time

def restart_line():
    sys.stdout.write('\r')
    sys.stdout.flush()

sys.stdout.write('some data')
sys.stdout.flush()
time.sleep(2) # wait 2 seconds...
restart_line()
sys.stdout.write('other different data')
sys.stdout.flush()

Answer 2

I just had this problem. You can still use \r, even in Windows Command Prompt, however, it only takes you back to the previous linebreak (\n).

If you do something like this:

cnt = 0
print str(cnt)
while True:
    cnt += 1
    print "\r" + str(cnt)

You'll get:

0
1
2
3
4
5
...

That's because \r only goes back to the last line. Since you already wrote a newline character with the last print statement, your cursor goes from the beginning of a new empty line to the beginning of the same new empty line.

To illustrate, after you print the first 0, your cursor would be here:

0
| # <-- Cursor

When you \r, you go to the beginning of the line. But you're already on the beginning of the line.

The fix is to avoid printing a \n character, so your cursor is on the same line and \r overwrites the text properly. You can do that with print 'text',. The comma prevents the printing of a newline character.

cnt = 0
print str(cnt),
while True:
    cnt += 1
    print "\r" + str(cnt),

Now it will properly rewrite lines.

Note that this is Python 2.7, hence the print statements.

Answer 3

easy method :)

import sys
from time import sleep
import os

#print("\033[y coordinate;[x coordinateH Hello")
os.system('cls')
sleep(0.2)
print("\033[1;1H[]")
sleep(0.2)
print("\033[1;1H  []")
sleep(0.2)
print("\033[1;1H    []")
sleep(0.2)
print("\033[1;1H      []")
sleep(0.2)
print("\033[1;1H        []")
sleep(0.2)
print("\033[1;1H      []")
sleep(0.2)
print("\033[1;1H    []")
sleep(0.2)
print("\033[1;1H  []")
sleep(0.2)
print("\033[1;1H[]")
sleep(0.2)

Answer 4

import sys 
import time

for i in range(10):
    print '\r',         # print is Ok, and comma is needed.
    time.sleep(0.3)
    print i,
    sys.stdout.flush()  # flush is needed.

And if on the IPython-notebook, just like this:

import time
from IPython.display import clear_output

for i in range(10):
    time.sleep(0.25)
    print(i)
    clear_output(wait=True)

http://nbviewer.ipython.org/github/ipython/ipython/blob/master/examples/notebooks/Animations%20Using%20clear_output.ipynb

Answer 5

Simple way if you're just wanting to update the previous line:

import time
for i in range(20):
    print str(i) + '\r',
    time.sleep(1)

Answer 6

I know this is old, but i wanted to tell my version (it works on my PC in the cmd, but not in the idle) to override a line in Python 3:

>>> from time import sleep
>>> for i in range(400):
>>>     print("\r" + str(i), end="")
>>>     sleep(0.5)

EDIT: It works on Windows and on Ubuntu