Torsten Mohr wrote:
I still wonder why a concept like "references" was not implemented in Python. I think it is (even if small) an overhead to wrap an object in a list or a dictionary.
Because Python uses a fundamentally different concept for variable names than C/C++/Java (and most other static languages). In those languages, variables can be passed by value or by reference; neither term really applies in Python. (Or, if you prefer, Python always passes by value, but those values *are* references.) Python doesn't have lvalues that contain rvalues; Python has names that are bound to objects. Passing a parameter just binds a new name (in the called function's namespace) to the same object.
It's also rather less necessary to use references in Python than it is in C et. al. The most essential use of references is to be able to get multiple values out of a function that can only return a single value. Where a C/C++ function would use the return value to indicate error status and reference (or pointer) parameters to communicate data, a Python program will return multiple values (made quick & easy by lightweight tuples and tuple unpacking) and use exceptions to indicate error status. Changing the value of a parameter is a side-effect that complicates reading and debugging code, so Python provides (and encourages) more straightforward ways of doing things.
Jeff Shannon Technician/Programmer Credit International
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