Functions: why use a variable "display" in a UDF as a Boolean

[MMartin71]

Hello,
Can someone explain why the following code includes the "display" variable in the function?

def full_name(first, middle, last, display):
      name = first + " " + middle + " " + last
      if display:
             print(name)
      return name

to call function:

full_name("John", "W", "Doe", True)
complete_name = full_name("John", "W", "Doe", False)
print(complete_name)

Also, is it necessary to use the complete_name line of code?
Couldn't you just use print(full_name("John", "W", "Doe")

buran write May-25-2025, 05:22 PM:
Please, use proper tags when post code, traceback, output, etc. This time I have added tags for you.
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[Axel_Erfurt]

If True it prints the name

def full_name(first, middle, last, display):
    name = f"{first} {middle} {last}"
    if display:
        return name


complete_name = full_name("John", "W", "Doe", False)
print(complete_name)

complete_name = full_name("John", "W", "Doe", True)
print(complete_name)

[deanhystad]

It does so because the author thought it should. It is not a design decision I would make.

[DeaD_EyE]

A function should return a value or print something, without returning anything.
If both is the case, your function has unwanted side effects.
Maybe the author of this function knows this and introduced the ability not to print, if the function is used.

But still, it's annoying if a function prints something, if you expect just a return value.
Sometime libraries are using excessive logging functions, which is also annoying, if activated by default. Then you've to deactivate this manually, if you do not want to have debug output in your program. Most people do not want this.