Project

General

Profile

Misc #15224

Updated by nobu (Nobuyoshi Nakada) 5 months ago

Today I looked at:

https://ruby-doc.org/core-2.5.1/Array.html#method-i-initialize_copy

The example to this method is this:
```ruby


a = [ "a", "b", "c", "d", "e" ]

a.replace([ "x", "y", "z" ]) #=> ["x", "y", "z"]

a #=> ["x", "y", "z"]
```


What confused me was that I was looking at the method called `initialize_copy` initialize_copy
but the example showed `.replace()`. .replace().

I then looked at `#replace` #replace there:

https://ruby-doc.org/core-2.5.1/Array.html#method-i-replace

And it was virtually identical to `initialize_copy`. initialize_copy.

I assume the examples for `.replace()` .replace() are correct; and perhaps `initialize_copy` initialize_copy
is just an alias? I am not sure, but I would like to suggest to make the documentation,
in particular the example, a bit more consistent.

When you click on "view source" to look at the C code, they show the very same
content, so I believe that initialize_copy is merely an alias to replace; but I tried
this and they are not fully equivalent:
```ruby


x = [1,2,3] # => [1, 2, 3]

x.initialize_copy [4,5,6]
```
```


Traceback (most recent call last):
2: from /System/Index/bin/irb:11:in `<main>'
1: from (irb):2

NoMethodError (private method `initialize_copy' called for [1, 2, 3]:Array)
```


Yet:
```ruby


x.replace [4,5,6] # => [4, 5, 6]
```


works. So I assume that `initialize_copy` initialize_copy is like `.replace()` .replace() but is a private
method instead.

Perhaps it may help to add a sentence below the documentation of
`replace()`, replace(), to explain what the use case for `initialize_copy` initialize_copy is. Or to perhaps
mention that it is an alias.

At the least how it is right now is that people may read initialize_copy,
but then see an example of #replace. (Perhaps an example for
initialize_copy may help, but either way, I think the current docu-example
is not ideal).

Back