Sorting by timestamp with uneven arrays

ruby-talk
1

Ok, this one is a little complicated and I'm sure there's a better way
to do it. Here's what I'm doing:

For presentation purposes, I have an array of arrays. Here's the
structure of the array:

[
"indicator (string that I set" ,
<model object from db, different models> ,
timestamp
]

I'm creating and inserting the timestamp myself, as each model object
has a form of timestamp, whether or not it's called that.

I'm doing it this way becuase I use a model method to get all of this
data, and the thing I want to do last is to sort by "timestamp".

array.sort_by won't work becuase it's not a hash (although i tried
adding a hash and then sorting by that hash, but that didn't work either
(got a nomethod error).

How can I make it so that I can sort this array?

Thanks so much in advance!

Mike

···

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2

You have an array of arrays, each of which has as its last element a
timestamp? You should just be able to do this: array.sort_by{|e|
e.last}

Or did I read this wrong?

Chris

···

On Dec 8, 3:03 pm, Mike Dershowitz <michael.dershow...@jpmchase.com> wrote:

Ok, this one is a little complicated and I'm sure there's a better way
to do it. Here's what I'm doing:

For presentation purposes, I have an array of arrays. Here's the
structure of the array:

[
"indicator (string that I set" ,
<model object from db, different models> ,
timestamp
]

I'm creating and inserting the timestamp myself, as each model object
has a form of timestamp, whether or not it's called that.

I'm doing it this way becuase I use a model method to get all of this
data, and the thing I want to do last is to sort by "timestamp".

array.sort_by won't work becuase it's not a hash (although i tried
adding a hash and then sorting by that hash, but that didn't work either
(got a nomethod error).

How can I make it so that I can sort this array?

Thanks so much in advance!

Mike
--
Posted viahttp://www.ruby-forum.com/.

3

Hi --

···

On Sun, 9 Dec 2007, Mike Dershowitz wrote:

Ok, this one is a little complicated and I'm sure there's a better way
to do it. Here's what I'm doing:

For presentation purposes, I have an array of arrays. Here's the
structure of the array:

[
"indicator (string that I set" ,
<model object from db, different models> ,
timestamp
]

I'm creating and inserting the timestamp myself, as each model object
has a form of timestamp, whether or not it's called that.

I'm doing it this way becuase I use a model method to get all of this
data, and the thing I want to do last is to sort by "timestamp".

array.sort_by won't work becuase it's not a hash (although i tried
adding a hash and then sorting by that hash, but that didn't work either
(got a nomethod error).

How can I make it so that I can sort this array?

Thanks so much in advance!

I'm not sure what you mean about #sort_by and being a hash. You can
use it on arrays.

Can you do this:

   array_of_arrays.sort_by {|array| array[-1] }

assuming timestamp is always the last thing in the array?

David

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4

I'm not sure why you are looking for a hash.

data = [
[ "model1", "instance of 1", Time.now],
[ "model2", "instance of 2", Time.now - 100]
]

p data.sort_by { |x| x[2] } # => [["model2", "instance of 2", Sat Dec 08 17:15:41 -0500 2007], ["model1", "instance of 1", Sat Dec 08 17:17:21 -0500 2007]]

Gary Wright

···

On Dec 8, 2007, at 5:03 PM, Mike Dershowitz wrote:

array.sort_by won't work becuase it's not a hash (although i tried
adding a hash and then sorting by that hash, but that didn't work either
(got a nomethod error).

5

thanks everybody, it worked!

···

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