Скачать или смотреть Understanding Why print Returns a Function Address Instead of a Value

Discover why your Python function returns an address when printed and learn the proper ways to output its return value effectively.
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Why Is Print Returning an Address Instead of a Function's Return Value?

When working with Python, you might encounter a situation where printing a function results in an output that is confusing or unexpected. Instead of getting a useful return value, you might see what appears to be the function's address in memory. This can leave programmers, especially beginners, scratching their heads. Let's delve into this phenomenon and explore how to resolve it effectively.

Understanding the Function and Its Return Value

Consider the following eligible function that determines if a person qualifies based on their age and language skills:

[[See Video to Reveal this Text or Code Snippet]]

This function checks if a person’s age is between 25 and 46 and verifies their languages. If the criteria are met, it returns "Eligible!" otherwise, it returns "Not Eligible!"

The Problem: Printing the Function

Here’s how you might try to use this function in practice:

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The issue arises in this line:

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Instead of displaying whether the user is eligible, it outputs something like this:

[[See Video to Reveal this Text or Code Snippet]]

This is the memory address where the function eligible is stored, not the return value that you expected.

Why Does This Happen?

In Python, everything is an object. This includes functions; hence when you use print on a function without calling it (i.e., without parentheses), Python returns the object's address. To properly see the result of the function, you need to ensure you're calling it instead.

How to Fix It

To see the actual return value of the eligible function, you need to either:

Store the result in a variable:

[[See Video to Reveal this Text or Code Snippet]]

Call the function directly inside the print statement:

[[See Video to Reveal this Text or Code Snippet]]

With these changes, you are now invoking the function which allows it to return the desired string instead of the function's memory address.

Conclusion

In summary, when you attempt to print a Python function without calling it, you receive the memory address instead of the return value. This is an essential concept for any Python programmer to understand, especially when debugging code that handles functions. Just remember to always use parentheses when you intend to retrieve the function's output, and you’ll be on your way to displaying meaningful results.

With this understanding, you can confidently handle function outputs in your Python programs and avoid the confusion of receiving function addresses in your prints. Happy coding!