Change variable in-place

Asked Apr 03 '17 at 00:44

Active Apr 03 '17 at 00:57

Viewed 34 times

I want to be able to modify a variable. F.e. :

b = 0
setbit(b,4)

I expect b to become 16. But as we know python is pass-by-assignment, not pass-by-value or pass-by-reference. My question is : Is this possible in some other way ?

The best shortcut I've come up with is :

def nbit(n) : return 1 << n

and then :

b |= nbit(4)

I would prefer a function like the first example.

asked Apr 03 '17 at 00:44

sten

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A function like the first example isn’t possible. I’d use `b |= 1 << 4`. – Ry- Apr 03 '17 at 00:48
If you are willing to convert `b` into a one-element list (`b=[0]`), then you can do `def setbit(b,n) : b[0]|=1 << n`. – DYZ Apr 03 '17 at 00:53
Python _is_ pass-by-reference. – TigerhawkT3 Apr 03 '17 at 01:14
@TigerhawkT3: *Python is pass-by-value. – Ry- Apr 03 '17 at 01:16
@Ryan - ...of the reference. – TigerhawkT3 Apr 03 '17 at 01:17
@TigerhawkT3: Yeah. Just trying to avoid confusion with other languages that have the same pass-by-value semantics but also an option to pass by reference, like C# and VB.NET. – Ry- Apr 03 '17 at 01:17

Change variable in-place

0 Answers0