[Python-ideas] Intermediate Summary: Fast sum() for non-numbers

[Terry Reedy]

On 7/15/2013 2:54 PM, David Mertz wrote:

> What concatenation is NOT is "addition as far as HUMANS are concerned".

Have you really never added together two or more shopping lists?

Have you never lengthened a string (such as a kite string) or rope by 
adding (concatenating) another piece?

Have you never added two piles of papers together by piling one on top 
of the other (and order matters here).

As I posted before, What HUMANS do not do is 'concatenate' things. Nor 
is addition by concatenation, as in the examples above, usually 
considered summation.

Summation usually implies condensation. Summing multiple numbers 
produces one number. With a mixture of + and - munbers, the sum may even 
be less in magniture than the largest. Summing up an hour meeting should 
produce a statement of, say, a minute or less. A concatenation of 
everything said is not a summation. Concatenation does not 'condense' or 
'reduce', and that, I think, is why some do not see sum as applying to 
sequence joining.

In Peano arithmetic, in math, addition of numbers (counts) amounts to 
concatenation of sequences of successor operators.

-- 
Terry Jan Reedy