By value or by reference?
olli at haluter.fromme.com
Mon Oct 18 18:13:39 CEST 2004
Jonathan Ellis wrote:
> Roger Irwin wrote:
> > Riccardo Rossi wrote:
> > > How does Python pass arguments to a function? By value or by reference?
> > By reference to an object....See the python tutorial.
> Wrong. Here is the difference between pass by reference and pass by
> value to CS types:
> > > > def foo(a): a = 1
> > > > i = 10
> > > > foo(i)
> > > > print i
> With pass-by-reference, i would now be 1. However, since python is
> pass-by-value, it remains 10.
It remains 10 because integers are immutable, so the function
code cannot modify the caller's variable anyway. However, if
you pass a mutable variable, things look a little different:
>>> def foo(a): a = 1
>>> i = 
>>> print i
Oliver Fromme, Konrad-Celtis-Str. 72, 81369 Munich, Germany
``All that we see or seem is just a dream within a dream.''
(E. A. Poe)
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