Print a line to STDERR and STDOUT in Python

By ANJANEYULU DEVARASETTY

In this tutorial, we will discuss how to print a line to STDERR and STDOUT in Python.

In Python, there are standard terms like Stdin, stderr, stdout, etc.

Let’s see about the terms,

Standard Input (stdin)

Standard Input reads the data from the user Input, and it acts based on the user instructions. It returns the user Input data as per the instruction given in the Program.

For this, Standard terms we need to import the sys library module.

import sys

Python = sys.stdin
for Lan in Python:
    if 'Stop' == Lan.strip():
        print('Found Stop so Terminating')
        exit(0)
    else:
        print('Message from User: {}'.format(line))

Output:

hello world

Message from user: hello world

Stop

Found Stop so Terminating

Standard Output (stdout)

Standard Output is used to return the User input of words directly to the Console.

import sys

Python = sys.stdout
String = 'Hello world', 'Welcome to Python'

for Lan in String:
    Python.write(Lan)

Output:

Hello world  welcome to Python

Standard Error (stderr)

Standard Error is used to return the data directly to the Console and it also return the error messages.

Here, we are trying to add integer to the string.

import sys

Hello  = sys.stdout
World  = sys.stderr

Lan  = 'Welcome', 'to Python'

for i in Lan:
    Hello.write(i)
    try:
        i += 2
    except:
        World.write('Error')

Output:

Welcometo python

errorerror

Also read: howdoi in Python