subtle wren
Hello guys, are function parameters necessary in python ? The majority of function I've seen so far doesn't make use of any parameters.
Because all variables defined in our main body (that is outside functions etc, are global variables so no need to pass them as arguments rights?)
Maybe when we will need to define a parameter is when a function is calling another function ?
shut wharfBOT
Hello guys, are function parameters necessary in python ? The majority of functi...
@subtle wren
Python help channel opened
hollow kestrel
it's entirely up to you how to define a function and its parameters, there's no rules. If you need a parameter, use a parameter, otherwise, don't
lethal sleet
Hello guys, are function parameters necessary in python ? The majority of functi...
hypothethically, imagine there was no + operator, and only an add function, would you prefer if that function took 2 parameters, or if it forced you to define global variables with specific names?
young sigil
to add to that, we should use function parameters when the alternative is reassigning global variables inside a function
hollow kestrel
yeah, write functions assuming they are ignorant of global data
subtle wren
hypothethically, imagine there was no ``+`` operator, and only an ``add`` functi...
2 parameters
lethal sleet
2 parameters
do you understand whats the point of parameters now?
hollow kestrel
they should be reusable in as many situations as possible
subtle wren
do you understand whats the point of parameters now?
hmm I believed using parameters allow more flexibility in writing codes, we are not restricted to only used specific variable name for eg
vapid ginkgo
I should add that beginner material doesn't tend to use parameters because the examples are relatively simple
subtle wren
to add to that, we *should* use function parameters when the alternative is reas...
oh you mean if I have defined a global variable in my code and assign it with a value, if ever the value of the variable is changing in our function, we should pass it as a parameter ?
vapid ginkgo
oh you mean if I have defined a global variable in my code and assign it with a ...
That's exactly what they mean
hollow kestrel
you cannot modify a global variable from a function without the global keyword
which should be avoided
subtle wren
yeah I see
vapid ginkgo
you cannot modify a global variable from a function without the `global` keyword
But you can mutate which adds to the danger
hollow kestrel
if anything it paints a better picture of the differences of assignment and mutation
young sigil
pretty much, I'm saying avoid using the global keyword. if you want to reassign a global variable, do it in global scope
# bad
a = 5
def foo():
global a
a -= 2
foo()
# good
a = 5
def foo(a): return a-2
a = foo(a)
if you have some data and functions that operate on that data and change it - what you want is, perhaps, an object, or just well yeah, calculate the new value and reassign it
tender edge
Feeling like you need to use the global keyword to assign to the global scope is when you know you might want to use a class based approach instead.
subtle wren
Thanks guys, really appreciate for the knowledge shared
tender edge
There are valid use cases for global keyword use, but they rarely come up.
surreal cedar
having functions use and modify variables in the global scope looks primitive/archaic to me, it's everywhere if you read the 1993 doom source code and it makes the code hard to follow
tender edge
I think multiprocessing is the only time I've used it seriously.
Because then the child processes might have data per and need setting via the initializer.
So it's kind of semantically apt.
I mean, there are other approaches that would work, but
¯_(ツ)_/¯
subtle wren
oh huys
guys*
just a quick question
when do you use the "return" keyword in a function?
hollow kestrel
when you want to use something calculated by the function outside of the function
def get_rectangle_area(length, width):
let's say I define this function for calculating the area of a rectangle
def get_rectangle_area(length, width):
return length * width
we can return the result
def get_rectangle_area(length, width):
return length * width
area = get_rectangle_area(10, 15)
now area will hold the result of 10 * 15
!e
def get_rectangle_area(length, width):
return length * width
area = get_rectangle_area(10, 15)
print(area)
:white_check_mark: Your 3.12 eval job has completed with return code 0.
150
return is also good for when you want to exit out of a function early because of some condition, you'll have multiple return statements in a function in that case
tender edge
The way I describe it is that the call of the function becomes a reference to the object given to the return keyword in the function.
def func():
return 123
var = func()
# like
var = 123```
subtle wren
yeah I see, okay so as a recap:
we can use return to leave a function based on some conditions
OR
We can use it whenever we need to store a value based on the function
hollow kestrel
yeah I see, okay so as a recap:
we can use return to leave a function based on ...
Here's an example of an "early return". You don't fully have to understand the exact code. It's something I would use when scripting for animation software
tender edge
When encountered, a return statement (usually) terminates the execution of a function. If an object is provided, the call to the function evaluates to that object.
hollow kestrel
def duplicate_selection():
selection = cmds.ls(sl=1)
if not selection:
return
cmds.duplicate(selection)
This function duplicates my selection, but first I need to check if I even have a selection at all. If I don't have a selection, I tell the function to stop there
subtle wren
yep I see, it's like an exit command
tender edge
In effect.
"Terminate with this being the result of this function."
Broadly. It gets a bit more involved with generators/yield.
tough mirage
In general global variables are bad and should be avoided if possible
so yes function parameters are really important
shut wharfBOT
Python help channel closed