Why do beginners confuse print() and return? — Python

print() and return are very different things, as all programmers come to learn eventually. And yet, you continuously hear the same question asked over and over by beginner programmers:

What is the difference between print() and return?

Responses to this question often give basic definitions of the two, and are often met with incredulity from more experienced programmers that these two things can be mixed up. I’ll give a basic definition of the two, suitable for beginners, but I’ll also attempt to answer the question that I never really see the experienced programmers tackle— why were these being mixed up in the first place?

Beginner Definitions of print() and return

Here are basic definitions of print() and return below. I recognise that these definitions will not satisfy more advanced programmers, but for the time being let’s keep it simple:

• print() is used to display text to a command prompt window.
• return is used to return a value from inside a function to code that lives outside a function.

These are two different things, right? So then…

Why the confusion?

The confusion comes because beginner programmers only really think in terms of one function at a time. Here’s an example of what I mean:

Beginners often start out with print() first. So when they write a function and call it, it will something like this:

def add(num1, num2):
    print(num1 + num2)

>>> add(1, 2)
3

Then they learn return and they incorporate it into their function. But they still need to print out what they returned, so the code looks something like this instead:

def add(num1, num2):
    return num1 + num2
>>> print(add(1, 2))
3

Running both versions of the code give you the same result — 3.

And herein lies the problem — because the beginner programmer sees the second example and questions why they needed to add return in the first place. After all — the first version of the code looked simpler by using print() directly, and it gave the exact same answer — so why use return ? What is it adding here?

Clearing the fog

The only way to really demonstrate the difference is to use more than one function call, like so:

def add(num1, num2):
    return num1 + num2
>>> num3 = add(1, 2)
>>> num4 = add(num3, 3)
>>> print(num4)
6

Here, we are calling add() once to add 1 and 2 together. return returns the value of this, 3, back to a variable. This variable is then fed back into the add() function again to add 3 to it. The final answer, 6, is what then gets printed out.

And here is where the difference between return and print() is truly shown. Because you need to use return to store the interim value in a variable to be then fed back into add() . It is impossible to replace return with print() for this reason — any attempts to do so lead to an exception (and a mess).

A Deeper Truth

So, this is obviously a simple problem — though I hope any beginner programmers reading this are helped in understanding the difference between the two.

But for advanced programmers, I believe there is a deeper truth to this, relevant to when we try to help out newcomers. When a newcomer asks about a problem, we shouldn’t just take the question at face value and give a correct, but possibly incomplete, answer. Rather, we should think about why this person struggled to understand whatever they were asking about in the first place, and tailor our answers thus.