On Thu, 10 May 2007 14:53:46 -0700, Gary Herron wrote: > Strings *are* passed by reference *always*. There is no copy and no > overhead. Efficiency is not based on length. Since the string is > immutable, nothing you do inside the function can change the string > outside the function.
Python does NOT support pass by reference. Nor does it do pass by value. Both of those models might describe what other languages do, but they don't describe what Python does. Python's passing model is different from both pass by reference and pass by value, and there are circumstances where Python seems to be acting as if it were doing one or the other. But it isn't. The model Python uses is often (but not often enough...) called "pass by object" or "call by sharing". http://effbot.org/zone/call-by-object.htm Some people argue that because the underlying C implementation of C-Python uses pass-by-reference of pointers, it's okay to say Python does too. That's an invalid argument. Not all Python implementations are written in C. PyPy doesn't even have pointers, being written in Python. Even if it did, what the underlying engine does internally is irrelevant to what the Python language does. What Python does is pass _objects_, not values or references. -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
