[Python-Dev] trunc() (original) (raw)

Daniel Stutzbach daniel at stutzbachenterprises.com
Thu Jan 24 22:09:54 CET 2008


On Jan 24, 2008 12:46 PM, Guido van Rossum <guido at python.org> wrote:

trunc() has well-defined semantics -- it takes a Real instance and converts it to an Integer instance using round-towards-zero semantics.

int() has undefined semantics -- it takes any object and converts it to an int (a concrete type!) using whatever rules it likes -- the definition of int is up to whatever the source type likes to do.

What are the use-cases for when trunc() vs int() should be used, and for when a class should define trunc vs int?

This might help clear up whether both deserve to be a built-in, as well provide a starting point for 3.0 best practices.

-- Daniel Stutzbach, Ph.D. President, Stutzbach Enterprises LLC



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