python - Output to the same line overwriting previous

22
votes

how to get output to the same line by overwriting previous received Timing(countdown) by NTP server. As shown below after each second timing is receiving in next row.

13:35:01

13:35:00

13:34:59

13:34:58

13:34:57

13:34:56

I want timing should be received in same row clearing previous one.

4
python

4 Answers

57
votes

You can use the "return"-character \r to return to the beginning of the line. In Python 2.x, you'll have to use sys.stdout.write and sys.stdout.flush instead of print.

import time, sys
while True:
    sys.stdout.write("\r" + time.ctime())
    sys.stdout.flush()
    time.sleep(1)

In Python 3.3, you can use the print function, with end and flush parameters:

    print(time.ctime(), end="\r", flush=True)

Note, however, that this way you can only replace the last line on the screen. If you want to have a "live" clock in a more complex console-only UI, you should check out curses.

import time, curses
scr = curses.initscr()
scr.addstr(0, 0, "Current Time:")
scr.addstr(2, 0, "Hello World!")
while True:
    scr.addstr(0, 20, time.ctime())
    scr.refresh()
    time.sleep(1)
curses.endwin()
5
votes

This will work like a champ:

print("This text is about to vanish - from first line", end='')
print("\rSame line output by Thirumalai")

output:

Same line output by Thirumalai from first line

0
votes

I am using python 2.7

python --version
Python 2.7.12 :: Anaconda 4.1.1 (64-bit)

and I am using this the following function as a hook to display the download progress, by using urllib.urlretrieve 

def hook(bcount , bsize, tsize ):
    str = "[ %3d%% of %10d] \r" % (bcount * bsize * 100/tsize , tsize)    
    print str,

urllib.urlretrieve (url, file_name, hook)

Explanation: the \r put the cursor at start of the line , and the comma avoid to print in a new line , if you have the same number of character for each print , this will do the trick

if you are curious about urllib and the hook I am using you'll find the doc https://docs.python.org/2/library/urllib.html

0
votes

Works in python3

But only for windows

import os
import time
while True:
    print(time.ctime())
    time.sleep(1)
    os.system('cls')