Re: [Python-ideas] More alternate constructors for builtin type

On Wed, May 08, 2019 at 08:14:50AM +1000, Cameron Simpson wrote:

On 08May2019 00:18, Greg Ewing wrote:

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Steven D'Aprano wrote:

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That suggests a possible pair of constructors: bytes.from_int(n) -> equivalent to b'%d' % n bytes.ord(n) -> equivalent to bytes((n,))

I don't see how bytes.from_int(n) is any clearer about what it does than just bytes(n). If we're going to have named constructors, the names should indicate *how* the construction is being done, not just repeat the type of the argument.

How about from_size(n) and from_ord(n)? The former to make a NUL filled bytes of size n, the latter to make a single byte bytes with element 0 having value n.

We already have from_size, it's just spelled bytes(n). I don't dislike from_ord as a name, although perhaps it ought to be fromord to match fromhex.

Preemptively one could argue for from_size having an optional fill value, default 0. I think I'm -0 on that because I can't imagine a likely use case and it would slightly slow down every use.

Wanting to fill a bytes object with something other than zeroes is probably uncommon. But for those who need it '\xFF'*n should do the job.

I think I'd argue for a from_iter instead, to support an arbitrary fill pattern/sequence.

We already have that, its spelled bytes(iterable). py> bytes(range(5)) b'\x00\x01\x02\x03\x04' -- Steven