Problem with assigning variables of type List

Peter Hansen peter at
Mon Aug 19 19:08:52 EDT 2002

Max M wrote:
> List and other complex objects are passe via reference and not by value
> for performance reasons.

Isn't it the case that *everything* is passed by reference in Python?
The only important thing is whether the object for which the reference 
is being passed is mutable or not.  For non-mutable objects, it looks 
a lot like pass-by-value and can lull you away from your state of 
vigilance about such issues.  Then you go and pass in a mutable like 
a list and you get into trouble.


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