[Tutor] "Print" behaviour inside a loop?
nequeo at gmail.com
Sun Jun 12 01:42:27 CEST 2005
Firstly, thanks to everyone who helped me find my own IP address. That
was a big help. That bit is working now, and working very nicely. I am
now stuck on something purely aesthetic - printing a few dots across the
screen to provide a bit of feedback while the VPN tunnel is being
ip_addr = ""
tries = 0
retries = 10
print "Connecting to %s" % (choice),
os.system("pon %s" % (choice))
while ip_addr == "" and tries < retries:
print "...", # This is the line causing problems
ip_addr = get_addr()
if ip_addr != '':
#create the route!
tries += 1
It works. The problem is, nothing is displayed on screen until after the
connection occurs - at which point we see:
"Connecting to Prodigi ... ... ... ... ... ... ... "
If I remove the comma at the end of the marked line, the ellipses print
every .5 seconds as desired, except they print down the screen of course!
After googling around a little, I found a post that seemed to say
Python won't draw the results of 'print' statements until it hits a
newline. I tried using sys.stout.write('...'), but had the same problem
there, too. I've also found a few progress bar classes around the web,
but I not exactly want a progress bar. I just want to print '...' every
few seconds until connected.
Any hints? I looked up the python reference manual, but couldn't find
any way to force print statements to draw. Should I be looking into
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