import time
def threedot():
time.sleep(0.5)
print '.',
time.sleep(0.5)
print '.',
time.sleep(0.5)
print '.'
threedot()
When the above code is run, the interpreter waits 1.5 seconds and then prints '. . .'; rather than wait 0.5 seconds in-between printing '.'. Why is this? (on python 2.7.3)
The output is being cached until one of several events which your code doesn't actually trigger until the final print. Flush the output (hint: sys.stdout.flush()) each time.
stdout is usually "line-buffered", meaning libc will buffer the output (and not write it to the console) until a newline is encountered, or the stream is closed.
Either write to stderr, or manually flush the output stream each time.
