How to use \r to print on same line?
Solution 1
Put the \r
at the beginning or end of your printed string, e.g. '\rthis string will start at the beginning of the line'
. or 'the next string will start at the beginning of the line\r'
. Conceptually, \r
moves the cursor to the beginning of the line and then keeps outputting characters as normal.
You also need to tell print not to automatically put a newline character at the end of the string. In python3, you can use end=""
as in this previous stackoverflow answer.
Alternatively, instead of using print you can do import sys
and sys.stdout.write('whatever')
, which sends only the exact characters to stdout without an implicit newline. You'll probably also want to use sys.stdout.flush()
, without which it will store characters in a buffer rather than printing them immediately.
Solution 2
Add an , end="\r"
to you print function. Also make sure your printed data has enough space to overwrite the previous printed data or be of the same length since just moving to the same line would not automatically clear the previous contents.
Solution 3
You can use sys.stdout.write
:
import time
import sys
def timer(t=5):
t0 = time.time()
now = t0
while now-t0 < t:
now = time.time()
timestr = '\r%%%i\t' %(100*(now-t0)/t)
sys.stdout.write(timestr)
sys.stdout.flush()
time.sleep(0.1)
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Santosh Kumar
Fullstack Developer at Method Studios. I love developing the backend. You can find me on Twitter.
Updated on August 12, 2022Comments
-
Santosh Kumar over 1 year
I have made a downloader:
#!/usr/bin/env python #-*- coding:utf-8 -*- from __future__ import print_function, division, absolute_import, unicode_literals import os import argparse try: from urllib2 import urlopen except ImportError: from urllib.request import urlopen # {{ Argument parser parser = argparse.ArgumentParser( prog='downloader', description='a featureful downloader' ) parser.add_argument( '-o', dest='outputfile' ) parser.add_argument( '-r', dest='remotefile' ) downloader = parser.parse_args() # }} # {{ default local filename if downloader.outputfile: default_output_file = downloader.outputfile else: default_output_file = os.path.split(downloader.remotefile)[-1] # }} u = urlopen(downloader.remotefile) meta = u.info() file_size = int(dict(meta.items())['Content-Length']) print("Downloading: %s Bytes: %s" % (default_output_file, file_size)) with open(default_output_file, 'wb') as f: file_size_dl = 0 block_sz = 8192 while True: buffer = u.read(block_sz) if not buffer: break file_size_dl += len(buffer) f.write(buffer) status = r"%10d [%3.2f%%]" % (file_size_dl, file_size_dl * 100. / file_size) status = status + chr(8)*(len(status)+1) print(status)
A sample run of this script would be:
python3 downloader.py -o ubuntu.iso -r http://releases.ubuntu.com/13.04/ubuntu-13.04-desktop-i386.iso
And a sample output will be:
Downloading: ubuntu.iso Bytes: 832569344 8192 [0.00%] 16384 [0.00%] 24576 [0.00%] 32768 [0.00%] 40960 [0.00%] 49152 [0.01%] 57344 [0.01%] 65536 [0.01%] 73728 [0.01%] 81920 [0.01%] 90112 [0.01%] 98304 [0.01%] 106496 [0.01%] 114688 [0.01%] 122880 [0.01%] 131072 [0.02%] 139264 [0.02%] 147456 [0.02%] 155648 [0.02%] 163840 [0.02%]
Note that as the loop goes the output is printed on a separate lines. I know I can use
\r
(carriage return) to do that. But I have confusion where and how to use that. -
Jonathan Hartley almost 8 yearsCute idea to use 'end', but I prefer to print the '\r' right before printing my value, not after. That way, anything else that gets printed (e.g. a traceback) doesn't overwrite the last printed value.