(newbie) Array > Element Assignment > nil > Documentation

ruby-talk
1

Ruby version : 1.9.1.376
OS : Windows

I'm checking http://ruby-doc.org/core/classes/Array.html#M002161 (Array
element assignment) which says
   ...If nil is used in the second and third form, *deletes* elements
from self...
with the example
   a[1..-1] = nil #=> ["A"]

This doesn't seem to agree with how Ruby works now. puts a.to_s gives me
   ["A", nil]
nil seems to work the way any other assignment would. The splice is just
replaced with the new element.

Am I reading this wrong?

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2

that's an old and buggy doc

try this 1.9 doc

  class Array - RDoc Documentation

btw, you can also use ri

eg

$ ri Array#=
Array#=

(from ruby core)

···

On Wed, Jun 9, 2010 at 4:39 PM, Potato Peelings <potato.peelings@gmail.com> wrote:

I'm checking class Array - RDoc Documentation (Array

------------------------------------------------------------------------------
  ary[index] = obj -> obj
  ary[start, length] = obj or other_ary or nil -> obj or other_ary or nil
  ary[range] = obj or other_ary or nil -> obj or other_ary or nil

------------------------------------------------------------------------------

Element Assignment---Sets the element at index, or replaces a subarray
starting at start and continuing for length elements, or
replaces a subarray specified by range. If indices are greater than
the current capacity of the array, the array grows automatically. A negative
indices will count backward from the end of the array. Inserts elements if
length is zero. An IndexError is raised if a negative index
points past the beginning of the array. See also Array#push, and
Array#unshift.

  a = Array.new
  a[4] = "4"; #=> [nil, nil, nil, nil, "4"]
  a[0, 3] = [ 'a', 'b', 'c' ] #=> ["a", "b", "c", nil, "4"]
  a[1..2] = [ 1, 2 ] #=> ["a", 1, 2, nil, "4"]
  a[0, 2] = "?" #=> ["?", 2, nil, "4"]
  a[0..2] = "A" #=> ["A", "4"]
  a[-1] = "Z" #=> ["A", "Z"]
  a[1..-1] = nil #=> ["A", nil]
  a[1..-1] = #=> ["A"]

best regards
-botp

3

botp wrote:

that's an old and buggy doc

try this 1.9 doc
  class Array - RDoc Documentation

Thanks! That resolves it.

btw, you can also use ri

This is nice. Thanks again.

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