Hello,

Im trying to learn ruby by using koans.

Now I have to fill in this part.

def test_some_system_objects_always_have_the_same_id
assert_equal --, false.object_id
assert_equal --, true.object_id
assert_equal --, nil.object_id
end

According to the answers I have to fill in like this :

def test_some_system_objects_always_have_the_same_id
assert_equal 0, false.object_id
assert_equal 2, true.object_id
assert_equal 4, nil.object_id
end

But how can I normally know the id of a object ?

Roelof

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  • Robert Walker at Sep 18, 2012 at 6:00 pm

    Roelof Wobben wrote in post #1076512:
    Hello,

    Im trying to learn ruby by using koans.

    Now I have to fill in this part.

    def test_some_system_objects_always_have_the_same_id
    assert_equal --, false.object_id
    assert_equal --, true.object_id
    assert_equal --, nil.object_id
    end

    According to the answers I have to fill in like this :

    def test_some_system_objects_always_have_the_same_id
    assert_equal 0, false.object_id
    assert_equal 2, true.object_id
    assert_equal 4, nil.object_id
    end

    But how can I normally know the id of a object ?
    puts false.object_id
    puts true.object_id
    puts nil.object_id

    --
    Posted via http://www.ruby-forum.com/.

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  • Christopher R. Maden at Sep 19, 2012 at 3:09 am

    On 09/18/2012 01:23 PM, roelof wrote:
    But how can I normally know the id of a object ?
    Meditate on the name of the test.

    ~Chris
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  • Rubyonrailsx at Sep 19, 2012 at 3:29 am
    As far as i know, ruby use memory location to generate object's id, normally any dynamic objects(runtime generate objects) will have different object_id, for example "foo".object_id not equal with "foo".object_id. But, any object like number, true, false ,nil and symbol all have fixed object_id

    --
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    On Wednesday, September 19, 2012 at 1:23 AM, roelof wrote:

    Hello,

    Im trying to learn ruby by using koans.

    Now I have to fill in this part.

    def test_some_system_objects_always_have_the_same_id
    assert_equal --, false.object_id
    assert_equal --, true.object_id
    assert_equal --, nil.object_id
    end

    According to the answers I have to fill in like this :

    def test_some_system_objects_always_have_the_same_id
    assert_equal 0, false.object_id
    assert_equal 2, true.object_id
    assert_equal 4, nil.object_id
    end

    But how can I normally know the id of a object ?

    Roelof

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  • Roelof at Sep 19, 2012 at 5:59 am
    Everybody thanks for the explanation.

    I have another problem.
    On this :

    def test_accessing_hashes_with_fetch
    hash = { :one => "uno" }
    assert_equal "uno", hash.fetch(:one)
    assert_raise("Class: <IndexError> Message: <"key not found">
    ---Backtrace--- ./about_hashes.rb:27:in `fetch' ./about_hashes.rb:27:in
    `test_accessing_hashes_with_fetch' ") do
    hash.fetch(:doesnt_exist)
    end

    I get always a syntax error.

    How to solve this one?

    Roelof


    Op woensdag 19 september 2012 05:29:59 UTC+2 schreef cming xu het volgende:
    As far as i know, ruby use memory location to generate object's id,
    normally any dynamic objects(runtime generate objects) will have different
    object_id, for example "foo".object_id not equal with "foo".object_id. But,
    any object like number, true, false ,nil and symbol all have fixed object_id

    --
    rubyonrailsx
    Sent with Sparrow <http://www.sparrowmailapp.com/?sig>

    On Wednesday, September 19, 2012 at 1:23 AM, roelof wrote:

    Hello,

    Im trying to learn ruby by using koans.

    Now I have to fill in this part.

    def test_some_system_objects_always_have_the_same_id
    assert_equal --, false.object_id
    assert_equal --, true.object_id
    assert_equal --, nil.object_id
    end

    According to the answers I have to fill in like this :

    def test_some_system_objects_always_have_the_same_id
    assert_equal 0, false.object_id
    assert_equal 2, true.object_id
    assert_equal 4, nil.object_id
    end

    But how can I normally know the id of a object ?

    Roelof

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  • Frederick Cheung at Sep 19, 2012 at 7:33 am

    On Sep 19, 4:29 am, rubyonrailsx wrote:
    As far as i know, ruby use memory  location to generate object's id, normally any dynamic objects(runtime generate objects) will have different object_id, for example "foo".object_id not equal with "foo".object_id. But, any object like number, true, false ,nil and symbol all have fixed object_id
    Although this is an implementation detail you'd be I'll advised to
    rely on - on my rubinius install for example the object id of nil is
    26

    Fred
    --
    rubyonrailsx
    Sent with Sparrow (http://www.sparrowmailapp.com/?sig)






    On Wednesday, September 19, 2012 at 1:23 AM, roelof wrote:
    Hello,
    Im trying to learn ruby by using koans.
    Now I have to fill in this part.
    def test_some_system_objects_always_have_the_same_id
    assert_equal --, false.object_id
    assert_equal --, true.object_id
    assert_equal --, nil.object_id
    end
    According to the answers I have to fill in like this :
    def test_some_system_objects_always_have_the_same_id
    assert_equal 0, false.object_id
    assert_equal 2, true.object_id
    assert_equal 4, nil.object_id
    end
    But how can I normally know the id of a object ?
    Roelof
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postedSep 18, '12 at 5:23p
activeSep 19, '12 at 7:33a
posts6
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