Bug #12765: An [element] multiply an number, every element in the list would be modified after modifying only one of then.

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin14]
• Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN

[fanjieqi (jieqi fan)]

element = [1] list = [element.clone] * 3 p list #[[1], [1], [1]] list[0][0] = -1 # should be [[-1], [1], [1]] p list # [[-1], [-1], [-1]]
The list initialized as [ [1], [1] ]. Then we assign the list[0][0], which is 1, as -1, and the list[1][0] is changed as -1 too.

[Hanmac (Hans Mackowiak)]

this is not much of a bug,

your array has three times the same element object (same object id)

you want:
list = Array.new(3) { [1] } #=> [[1], [1], [1]]

list[0][0] = -1

list #=> [[-1], [1], [1]]

[fanjieqi (jieqi fan)]

element = [1] list = Array.new(3) { element } p list #[[1], [1], [1]] list[0][0] = -1 # should be [[-1], [1], [1]] p list # [[-1], [-1], [-1]]
OK, and could you please figure out this one?

[marcandre (Marc-Andre Lafortune)]

• Status changed from Open to Rejected

Clearly not a bug.

list[0][0] = -1 # => same as doing:
element[0] = -1

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