Access Hash in the same order that was created

[Mario Ruiz]

I need to access to a Hash in the same order that It was created:

mh=Hash.new()
mh["one"]="1"
mh["two"]="2"
mh["three"]="3"
mh["four"]="4"

mh.each {|val|
puts val[0]
}

In this example I get:
three
two
one
four

and I would like to get:
one
two
three
four


is that possible?

Thanks

 

[7stud --]

I need to access to a Hash in the same order that It was created:
is that possible?

Thanks

No.

 

[ara.t.howard]

I need to access to a Hash in the same order that It was created:

mh=Hash.new()
mh["one"]="1"
mh["two"]="2"
mh["three"]="3"
mh["four"]="4"

mh.each {|val|
puts val[0]
}

In this example I get:
three
two
one
four

and I would like to get:
one
two
three
four


is that possible?

Thanks

gem install orderedhash

mh = OrderedHash.new
...
...


etc.

a @ http://codeforpeople.com/

 

[ara.t.howard]

is that possible?

forgot to mention - 1.9 does this by default now.

a @ http://codeforpeople.com/

 

[Gregory Seidman]

I need to access to a Hash in the same order that It was created: [...]
is that possible?

First off, this is not a hash. Hashes are inherently unordered. Hashes
provide amortized O(1) insertion and retrieval of elements by key, and
that's it. If you need an ordered set of pairs, use an array of arrays.
Yes, this is a pet peeve of mine.

There was an OrderedHash that someone wrote, but needing it is an
indication of a design problem. It has also been obsoleted by the
Dictionary in Ruby Facets.

One could argue that, like Java, there should be a standard Dictionary
interface that Hash implements, and that there should be another
implementation that preserves order without guaranteeing anything about
performance. That's not how things stand right now.

Thanks

--Greg

 

[Gennady Bystritsky]

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bnRyaWVzIGJhc2VkIG9uIGtleXMuDQoNCkdlbm5hZHkuDQo=

 

[Tor Erik Linnerud]

is that possible?

Hash preserves insertion order in Ruby 1.9

irb(main):026:0> RUBY_VERSION
=> "1.9.0"
irb(main):027:0> mh.each{|val| puts val[0]}
one
two
three
four

regards,
Tor Erik

 

[Simon Krahnke]

I need to access to a Hash in the same order that It was created:

mh=Hash.new()
mh["one"]="1"
mh["two"]="2"
mh["three"]="3"
mh["four"]="4"

mh.each {|val|
puts val[0]
}

In this example I get:
three
two
one
four

and I would like to get:
one
two
three
four


is that possible?

The Hash doesn't remember the order in which you put the values in.

If the order is important not easily reconstructable, you have to
store the keys in an Array.

mfg, simon .... l

 

[Mario Ruiz]

Thanks to everybody