[wahern]

Relatedly, a survey of array nomenclature was performed for the ISO C committee when choosing the name of the new countof operator: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3469.htm

It was originally proposed as lengthof, but the results of the public poll and the ambiguity convinced the committee to choose countof, instead.

[pansa2]

The reason many languages prefer `length` to `count`, I think, is that the former is clearly a noun and the latter could be a verb. `length` feels like a simple property of a container whereas `count` could be an algorithm.

`countof` removes the verb possibility - but that means that a preference for `countof` over `lengthof` isn't necessarily a preference for `count` over `length`.

[ncruces]

But count is more clearly a dimensionless number of elements, and not a size measured in some unit (e.g. bytes).

[zahlman]

When I see "countof" I expect an operation that lets me filter the container and tell me the count of things that meet some condition (probably described with a unary predicate, but perhaps just an element to check for equality).