Learning Python - Pointers

Python Pointers; or lack there of
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[@thatlazyburger9855]

Thanks a lot. I have a test tomorrow and this is gonna help big time. Ty

[@Alireza13488]

Very good video, but It is also worth mentioning, pointers do exist for arrays or any other mutable object in python

[@Code-Militia]

Thank you for the update! Will correct myself in a future video.

[@user-wk6mb7mw3g]

Python does have pointers. Try your simple demonstration on "lists".

[@frodobaggins3974]

Hehe, try this: a = [1, 2, 3] b = a a.append(4) print(b) Surprised? :)

[@Code-Militia]

I will try this out and figure out why the result is the result. Thank you so much!

[@predator1011X]

@@Code-Militia i would like to know this too

[@frodobaggins3974]

@@predator1011X Short answer: memory management. Lists are mutable objects, once you create a list, and make a link between the variable name (also an object in Python!) and the list object, the link holds even if you change the content of the linked object (a list in this case). Same goes for sets, dicts and user-created classes. It's rooted in the 'everything is an object' ideology. So if you want to mimic a pointer behaviour in Python, contain the variable value in a list. Saying this, in C++ we use pointers for speed and for smarter memory management. In Python you will not see any of these benefits, as the list is stored as an object anyway, not a simple addressed heap value. But yeah, it's there, and it works - if you need it.

[@ranitchatterjee5552]

No, xD!!

[@exoticme4760]

PIN THIS

[@basictech9069]

made a 5 min video to tell python dosent have pointers?? seriously???

[@arjunmehta2853]

It's for people who don't even know what pointers are.

[@mykhailoshpakov6487]

As I got, when you assign 5 to x , you assign to x a memory location , where instance of int class is stored. Then, since int is unchangeable type of data, once you assign 9 to x , you create another instance of int class which is stored at another location. Variable y points to precedent memory location, where 5 is stored. Could you answer me, is there any practical way to pass inside a function a variable , change it inside the function so that global variable changes also ?

[@Code-Militia]

Good question, yes there is a way to change a global function from a local variable by using the global keyword. Although, in my experience, I’ve never had to change the global variable from a local function. I’ve used global lists and dictionaries and always added keys and items to the list. Don’t need to use the global keyword then. thispointer.com/python-how-to-use-global-variables-in-a-function/

[@mykhailoshpakov6487]

@@Code-Militia Ok. Have a Nice day !

[@Code-Militia]

You too. Hope I was able to help.

[@casualgamingz153]

Try on lists lil bro

[@mykhailoshpakov6487]

Thank you for tutorial

[@Code-Militia]

You're welcome 😊

[@drac8854]

Is there a way to get value from id For example lets say i do x=10 y=id(x) Now how can i print value of y because now if i print value of y it will be an integer which is memory I want to print whats at that memory Like address(&) in c

[@Code-Militia]

While you can loop through globals().values() to get the ID and return the value, it's not best practice because there are too many variables to go through and your app could be slowed down by a lot. >>> x = 10 >>> xAddress = id(x) >>> [y for y in globals().values() if id(y)==xAddress] [10, 10] >>>

[@frodobaggins3974]

Without checking first whether this particular ID exists? No and there are good reasons for not doing it. If Python interpreter tried to access memory address that was not allocated to it in the first place (which is likely the case), it would have caused a segmentation fault and the interpreter would be unconditionally killed by the operating system (SIGSEGV). Programs cannot read memory that has not been allocated to them... If you're interested in further explanation read about dereferencing null pointers in C - as this is what you somewhat try to achieve.

[@raayaansahu2525]

ahaha lovely kinda hilarious though

[@Code-Militia]

Finally, someone finds it funny 😄

[@Mogwai88]

What color scheme are you using here?

[@Code-Militia]

I use fish shell with sushi color scheme, this particular set of colors is from VSCode shell with bpython running, and that’s not a typo.

[@shambhav9534]

So, you just trolled me? I wanted to use pointers in python, I knew it wasn't possible, then I saw the title, got so happy, then... all went down... And btw C has pointers, that's stupid of you to be uncertain, C++ is just C but more OOP and with modern syntax, and more tools, only more tools, not like C++ has any more features.

[@Code-Militia]

You’re right, that was an unprofessional jerk move by me. I’ll put a troll tag

[@amritlohia8240]

Actually it *is* possible, through the ctypes module. See e.g. here: kzbin.info/www/bejne/opTPc2WPZ5ehl9E.