Ruby - hash to array

Question

I have:

a =  [{"_id"=>BSON::ObjectId('569a58b8e301d083c300000c')}]

and I want it to be:

[BSON::ObjectId('569a58bee301d083c3000752')]

I was experimenting with

a.map{|e| e.map{|k, v| v }}

but it gives me nested array:

[[BSON::ObjectId('569a58b8e301d083c300000c')]]

I'll appreciate any help.

Stefan · Accepted Answer · 2016-06-01 12:51:30Z

3

If you just had a hash:

h = {"_id"=>BSON::ObjectId('569a58b8e301d083c300000c')}

and you wanted to fetch the BSON::ObectId, you would call Hash#[]:

h["_id"] #=> BSON::ObjectId('569a58b8e301d083c300000c')

The same works with map:

a.map { |h| h["_id"] }
#=> [BSON::ObjectId('569a58b8e301d083c300000c')]

answered Jun 1, 2016 at 12:51

Stefan

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2 Comments

Thank you, stupid of me not to think about that. Have a nice day!

Not just [a.first["_id"]]?

Ropeney · Accepted Answer · 2016-06-01 13:30:17Z

0

A cleaner solution.

a = [{"id"=>"1234"},{"id"=>"9876"}]
a.flat_map(&:values)
=> ["1234", "9876"]

answered Jun 1, 2016 at 13:30

Ropeney

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AJFaraday · Accepted Answer · 2016-06-01 13:34:56Z

0

I'd use values, then call flatten.

a.collect(:&values).flatten

Or, if there'll only ever be one value

a[0].values[0]

answered Jun 1, 2016 at 13:34

AJFaraday

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