Feature #21300: Suggestion: Method for Array truncation

• Status: Open
• Assignee: -
• Target version: -

[sigsys (Math Ieu)]

#pop(n) and #slice!(...) can be used for truncation, but they both allocate a new array for the deleted elements (unless you do it one at a time with #pop()...), which is not always needed.

I propose adding a #size= method for truncating without allocating a new array:

a = [10, 20, 30]
a.size = 2
a # [10, 20]

Growing the array could be allowed as well...

a = [10, 20]
a.size = 4
a # [10, 20, nil, nil]

[Eregon (Benoit Daloze)]

Using ary.size = feels unidiomatic Ruby to me, it feels very low level and not very expressive about the intent (e.g. it's not clear if shrinking or growing).

I don't think pop(n) returning an Array is big overhead, i.e., I don't think there is enough reason to add another Array method for this rarely-needed case.