Chris Rebert wrote:
I think the point made by Grant Edwards is instructive. len(x) = 1
typically implies list(x)[0] and similar should be valid.
At least, one should be able to iterate with x and get len(x) items.
See below.
And there's nothing ambiguous about len(42).
Really? What is its value then? I think arguments of varying quality
can be made for:
1 - as the OP and those from array programming languages would suggest
2 - the number of decimal digits in 42, if one was feeling Perlish
6 - the minimum number of bits necessary to represent 42 in binary
32 (or 64, depending on your CPU) - the number of bits necessary to
represent an int (obviously breaks down a bit with arbitrary-magnitude
ints)
undefined - i.e. it causes an error, the current behavior; asking for
the length of a non-collection is "nonsensical" or "absurd"
In set theory, one can define counts recursively as follows
0 = {} (set, not dict)
n+1 = n | {n}
so len(n) = n, and in particular, len(42) = 42.
On the same basis, it has been proposed (and rejected) that iter(n) ==
range(n), do that we could write 'for i in 10' for instance. Guido
thought this too esoteric.
Terry Jan Reedy
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