[Python-Dev] Rationale for sum()'s design? (original) (raw)

Greg Ewing greg.ewing at canterbury.ac.nz
Tue Mar 15 00:20:07 CET 2005

Guido van Rossum wrote:

But I think the logical consequence of your approach would be that sum([]) should raise an exception rather than return 0, which would be backwards incompatible. Because if the identity element has a default value, the default value should be used exactly as if it were specified explicitly.

In that case I would argue in favour of keeping it the way it is, since...

currently sum([1,1], 40) equals 42.

...seems quite reasonable to me. Or at least as reasonable as anything else.

-- Greg Ewing, Computer Science Dept, +--------------------------------------+ University of Canterbury, | A citizen of NewZealandCorp, a | Christchurch, New Zealand | wholly-owned subsidiary of USA Inc. | greg.ewing at canterbury.ac.nz +--------------------------------------+

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