In Python >= 3.4, you can make it a bit more elegant by creating a _RedirectStream context manager.

import contextlib
import io

class redirect_stdin(contextlib._RedirectStream):
    """Context manager for temporarily receiving stdin from another source."""
    _stream = "stdin"

def test():
    a = input("Type something: ")
    return a

if __name__=='__main__':
    with redirect_stdin(io.StringIO("Hello World")):
        returnValue = test()

This can be combined with the existing redirect_stdout and redirect_stderr decorators for even more flexibility. Somehow, stdin was not given the same treatment. You can read the diucussion on Python Issue #15805 for more context.

There's a few ways to do it.

• sys.stdin is a file-like object on which you can call functions read or readlines if you want to read everything or you want to read everything and split it by newline automatically. (You need to import sys for this to work.)

• If you want to prompt the user for input, you can use raw_input in Python 2.X, and just input in Python 3.

• If you actually just want to read command-line options, you can access them via the sys.argv list.

You will probably find this Wikibook article on I/O in Python to be a useful reference as well.

I was googling how to do this myself and figured it out. For my situation I was taking some sample input from hackerrank.com and putting it in a file, then wanted to be able to use said file as my stdin, so that I could write a solution that could be easily copy/pasted into their IDE. I made my 2 python files executable, added the shebang. The first one reads my file and writes to stdout.

Copy#!/Users/ryandines/.local/share/virtualenvs/PythonPractice-U9gvG0nO/bin/python
# my_input.py
import sys

def read_input():
    lines = [line.rstrip('\n') for line in open('/Users/ryandines/Projects/PythonPractice/swfdump')]
    for my_line in lines:
        sys.stdout.write(my_line)
        sys.stdout.write("\n")

read_input()

The second file is the code I'm writing to solve a programming challenge. This was mine:

Copy#!/Users/ryandines/.local/share/virtualenvs/PythonPractice-U9gvG0nO/bin/python
def zip_stuff():

    n, x = map(int, input().split(' '))
    sheet = []

    for _ in range(x):
        sheet.append( map(float, input().split(' ')) )

    for i in zip(*sheet): 
        print( sum(i)/len(i) )

zip_stuff()

Then I use the operating system's pipe command to provide the buffering of STDIN. Works exactly like hackerrank.com, so I can easily cut/paste the sample input and also my corresponding code without changing anything. Call it like this: ./my_input.py | ./zip_stuff.py

Here's one way:

import ast
line = '1 2 3 4 5'
list(ast.literal_eval(','.join(line.split())))
=> [1, 2, 3, 4, 5]

The idea is, that for each line you read you can turn it into a list using literal_eval(). Another, shorter option would be to use list comprehensions:

[int(x) for x in line.split()]
=> [1, 2, 3, 4, 5]

The above assumes that the numbers are integers, replace int() with float() in case that the numbers have decimals.