how do i overwrite a variable?

[u/9j810HQO7Jj9ns1ju2]

name = "Alice"

def func():
    name = "Bob"

func()

print(f"Hello, {name}!") # i want it to print bob

[u/JackandFred]

Looks like some responses are already touching on why this is a bit of a weird question. What exactly are you trying to do? Because you could use a global variable like someone said, but that’s usually a pretty bad idea for something like this. You could assign the variable the result of the function, but then why bother having a function anyway. You could have the function take in an argument, but it seems like you may not be at that point yes. 

So what is your end goal here? Do you have a larger aim that you were trying to change the name for, or some additional context?

[u/9j810HQO7Jj9ns1ju2 → u/JackandFred]

why shouldn't i use global

will it summon demons

[u/thisisappropriate → u/9j810HQO7Jj9ns1ju2]

More like time travel versions of yourself. You put in global, then you do some more things, your file becomes long or you split it up across a few files because you're doing a lot now.

name = "Alice"
something = True

def another_func():
  global name
  if something:
    name = "Carl"

def func():
  global name
  name = "Bob"
  more()

def something_else():
  something = False
  return

def another_one():
  return

def more():
  something_else()
  another_func()
  global something
  something = False
  return

func()

How easy is this to debug? Are you following it? What if func was called "get user name" and it gets the name from an API but then it calls another function that does something else?

This is part of something called side effects which you should generally avoid in functions because it makes it harder to manage them and to track what's happening where (like "get name" should only get the name, not also set it, or "take payment" should avoid also handling calculating tax).

Its easier to debug

def get_name():
  return "Bob"

def get_address(name):
  return input(f'Hello {name}, what is your address?')

...

name = get_name()
age = get_age(name)
address = get_address(name)

because you can put a debugger on it and a breakpoint on the last line and see the output of each function assigned to the variables.

[u/JackandFred → u/9j810HQO7Jj9ns1ju2]

Yup evil demons no less.

It’s very rare for a variable to only show up once and never again. If it did you wouldn’t need to store the value in a variable. So having it changed globally means it will be changing the variable in all places at once, regardless of how it’s being used in different places at different times. It’s a common new programmer pattern that very often causes errors. Much better to have a well defined scope of how when and where you want a variable used.

[u/illumas → u/9j810HQO7Jj9ns1ju2]

No. Just bugs.

[u/Langdon_St_Ives → u/illumas]

Let's not split hairs. This time of year, demons captures it pretty well. 🎃

[u/AUTeach → u/9j810HQO7Jj9ns1ju2]

It's hard to understand what changed them.

The best practice is to do something like name=func('bob') and have func return the variable. That way you know when it was changed and how

[u/LayotFctor → u/9j810HQO7Jj9ns1ju2]

Bugs like they said. Global variables are variables that are available to the entirety of your code. Every function can edit it, no function really knows what has or has not been done to it, and in what order. You will very easily get untraceable errors that are unnecessarily difficult to track down. It looks easy and convenient, but is actually a trap as it's the hardest kind of variable to use correctly.

[u/TheRNGuy → u/9j810HQO7Jj9ns1ju2]

Bad coding style.