Why does returning in Interactive Python print to sys.stdout?

Question

I ran into something different today. Consider this simple function:

def hi():
    return \'hi\'

If I call it in a Python shell,

Answer 1

Most interactive shells use a REPL loop - read-eval-print.

They read your input. They evaluate it. And they print the result.

Non-function examples are (using the ipython shell):

In [135]: 3+3
Out[135]: 6    # result of a math operation

In [136]: x=3    # no result from an assignment

In [137]: x
Out[137]: 3    # evaluate the variable, and print the result - its value