About sys.stdin and sys.stdout

sys.stdin and sys.stdout are file objects which are used by the interpreter for standard input and standard output. Data received by raw_input comes from stdin, which is normally connects to the keyboard. stdin can be redirected so that input instead comes from a file. This can be very useful for automating scripts.

About sys.stdout.write() and print()

When you call the print(obj) function, it actually call the sys.stdout.write(obj + '\n') like below:

import sys
sys.stdout.write("hello" + "\n")
print(hello)

About sys.stdin.readline() and input()

The input() function first takes the input from the user and then evaluates the expression. Python automatically identifies whether the user entered a string or a integer or a list.

Note

• Whatever you enter as input, input function converts it into a string.

The sys.stdin.readline() reads the escape character entered by the user, like below

import sys

name = sys.stdin.readline()
print(name)

num = sys.stdin.readline(2)
print(num)

Output

# Input Alison
'Alison\n'
# Input 1234
'12'

Differences between input() and sys.stdin.readline() functions:

References:

• Python Docs
• GeeksforGeeks