What is the Print Flush In Python? [closed]

The print uses stdout , like C. This is nothing more than the "file" in the operating system where the text output of a program is sent, and thus can be shown to the user. p>

By default, stdout is buffered; that is, it stores the data it receives without showing it until it receives the special newline code \n .

The print function of Python automatically automatically boosts a newline character in any string you send to it. But sometimes this behavior is not desired and you want to use two prints to show something on the same line. In this case, you will use the end argument of the print function to end the string with something other than the newline character (or with an empty string, so that you do not print anything other than what you ordered).

For example, you can expect the following code to print several dots on the same line, one every 0.5s:

import time

for _ in range(5):
    print('.', end='')
    time.sleep(0.5)
print(' Pronto!')

But what really happens in most cases is that nothing happens for 2.5s and then all the dots appear at once.

This happens because stdout by default shows nothing until it receives a new line, which we are not sending until the end.

So how do we remedy this problem?

Simple, just use flush to force the result to appear immediately, even without a new line:

import time

for _ in range(5):
    print('.', end='', flush=True)
    time.sleep(0.5)
print(' Pronto!')

It is worth mentioning that flush as argument pro print is only available from Python 3.3. Before that, it had to be called manually:

import sys
import time

for _ in range(5):
    print('.', end='')
    sys.stdout.flush()
    time.sleep(0.5)
print(' Pronto!')