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How to pass by reference in Python?

I just discovered that there are no ways to pass a var by reference in Python. From what I've seen this does not even exist in this language, which sounds strange to me, because I'm used to languages ​​derived from C, such as C# or C++, for example. The question is, if this does not actually exist in Python, how can I get the same result?

30th Jul 2018, 2:28 AM
Filipe
Filipe - avatar
4 Antworten
+ 2
strawdog Technically, yes, but you cannot assign to them in the function body: def x(y): x = 2 # here, x becomes a local variable inside the function a = 1 print(a) # 1 x(a) print(a) # still 1 You can still mutate mutable structures, like lists, though: def x(y): y.append(2) a = [1] print(a) # [1] x(a) print(a) # [1, 2] Anyway, essentially, passing by reference is limited and can't be controlled by the programmer. Mutable objects (lists, dicts, class objects, etc.) can be used as a reference, but immutable objects cannot, and reassigning anything makes it a local variable (excluding **kwargs, that's a topic for another day). I think the purpose of this was to make the language easier to understand, and have only one way of doing things, a Python philosophy.
30th Jul 2018, 12:23 PM
LunarCoffee
LunarCoffee - avatar
30th Jul 2018, 3:20 AM
LunarCoffee
LunarCoffee - avatar
+ 1
The point is that in Python every var IS a reference. >>> var = "a variable" >>> def checkid(x): print(id(x)) print(id(var)) >>> id(var) 48941960 >>> checkid(var) 48941960 48941960 >>>
30th Jul 2018, 8:28 AM
strawdog
strawdog - avatar
+ 1
Thank you guys!
30th Jul 2018, 8:37 PM
Filipe
Filipe - avatar