sys.stdout is not flushed
Jankins
-->1%
Here is my program ‘test.py’:
from sys import stdout
for v in range(10):
stdout.write('-->%d' % v)
stdout.flush()
else:
stdout.write('done!')
#end for
Then, I use 'python -u test.py' to run this script. But what I get
is :
-->0-->1-->2-->3-->4-->5-->6-->7-->8-->9done!
I am suppose to get 'done!'.
Can anybody help me about this?
Thanks.
Jankins
Diez B. Roggisch
> I am trying to use sys.stdout to print out "process-bar" like:
> -->1%
>
>
> from sys import stdout
> for v in range(10):
> stdout.write('-->%d' % v)
> stdout.flush()
> else:
> stdout.write('done!')
> #end for
>
> Then, I use 'python -u test.py' to run this script. But what I get
> is :
> -->0-->1-->2-->3-->4-->5-->6-->7-->8-->9done!
>
> I am suppose to get 'done!'.
>
> Can anybody help me about this?
You misunderstand what "flush" means. It is not about clearing the
screen, or the line.
Try printing
stdout.write('\r-->%d')
Diez
Jankins
> Jankins schrieb:
>
>
>
>
>
> > I am trying to use sys.stdout to print out "process-bar" like:
> > -->1%
>
>
> > from sys import stdout
> > for v in range(10):
> > stdout.write('-->%d' % v)
> > stdout.flush()
> > else:
> > stdout.write('done!')
> > #end for
>
> > Then, I use 'python -u test.py' to run this script. But what I get
> > is :
> > -->0-->1-->2-->3-->4-->5-->6-->7-->8-->9done!
>
> > I am suppose to get 'done!'.
>
> > Can anybody help me about this?
>
> You misunderstand what "flush" means. It is not about clearing the
> screen, or the line.
>
> Try printing
>
> stdout.write('\r-->%d')
>
> Diez
It works. I did misunderstood the meaning the 'flush'.
Thanks so much.
Jankins
>
>
>
>
>
> > I am trying to use sys.stdout to print out "process-bar" like:
> > -->1%
>
>
> > from sys import stdout
> > for v in range(10):
> > stdout.write('-->%d' % v)
> > stdout.flush()
> > else:
> > stdout.write('done!')
> > #end for
>
> > Then, I use 'python -u test.py' to run this script. But what I get
> > is :
> > -->0-->1-->2-->3-->4-->5-->6-->7-->8-->9done!
>
> > I am suppose to get 'done!'.
>
> > Can anybody help me about this?
>
> You misunderstand what "flush" means. It is not about clearing the
> screen, or the line.
>
> Try printing
>
> stdout.write('\r-->%d')
>
> Diez
But there is still a problem. When you use control character '\r', you
actually move to the head of the current buffer line and overwrite it.
So if I use this way:
for i in range(100, 0,-1)
The tail of the buffer is not overwrote.
How to solve this problem?
Thanks.
Cousin Stanley
>> ....
>> You misunderstand what "flush" means. It is not about
>> clearing the screen, or the line.
>>
>> Try printing
>>
>> � �stdout.write('\r-->%d')
>>
>> Diez
>
>
> But there is still a problem. When you use control character '\r',
> you actually move to the head of the current buffer line and
> overwrite it.
>
> So if I use this way:
> for i in range(100, 0,-1)
>
> The tail of the buffer is not overwrote.
The following version works ok for me
using python2.5 under debian linux ....
import sys
import time
for n in range( 11 ) :
sys.stdout.write( '\r Working ----> %d ' % n )
sys.stdout.flush()
time.sleep( 1 )
else :
print "\n"
print " That's all, folks !"
print " Adios ........... "
--
Stanley C. Kitching
Human Being
Phoenix, Arizona
Dave Angel
No idea what you mean by "buffer line." This is moving the cursor
around on the console.
Anyway, for such a loop, just make sure all the strings are the same
length. Or just cheat and always write a few blanks at the end.
sys.stdout.write("\r -- %5d" % i)
should do it, for up to 5 digit values
DaveA
Jankins
Thanks. It works. Put some space at the end of the output string.
Jankins
'%5d' is elegant. I prefer adding some space at the end of the output
string.
Thanks.
Nobody
> Try printing
>
> stdout.write('\r-->%d')
^M-->0^M-->1^M-->2^M-->3... ;)
But it's probably good enough for the OP's purposes.