Mapping to the Keys of a Hash

Question

I am working with a hash called my_hash :

{"2011-02-01 00:00:00+00"=>816, "2011-01-01 00:00:00+00"=>58, "2011-03-01 00:00:00+00"=>241}

First, I try to parse all the keys, in my_hash (which are times).

my_hash.keys.sort.each do |key|
  parsed_keys << Date.parse(key).to_s
end 

Which gives me this :

["2011-01-01", "2011-02-01", "2011-03-01"]

Then, I try to map parsed_keys back to the keys of my_hash :

Hash[my_hash.map {|k,v| [parsed_keys[k], v]}]

But that returns the following error :

TypeError: can't convert String into Integer

How can I map parsed_keys back to the keys of my_hash ?

My aim is to get rid of the "00:00:00+00" at end of all the keys.

Solution 1

Why don't you just do this?

my_hash.map{|k,v| {k.gsub(" 00:00:00+00","") => v}}.reduce(:merge)

This gives you

{"2011-02-01"=>816, "2011-01-01"=>58, "2011-03-01"=>241}

Solution 2

There is a new "Rails way" methods for this task :)

http://api.rubyonrails.org/classes/Hash.html#method-i-transform_keys

Solution 3

Using iblue answer, you could use a regexp to handle this situation, for example:

pattern = /00:00:00(\+00)+/
my_hash.map{|k,v| {k.gsub(pattern,"") => v}}.reduce(:merge)

You could improve the pattern to handle different situations.

Hope it helps.

Edit:

Sorry, iblue have already posted the answer

Solution 4

Another alternative could be:

1. map
2. return converted two elements array [converted_key, converted_value]
3. convert back to a hash

irb(main):001:0> {a: 1, b: 2}.map{|k,v| [k.to_s, v.to_s]}.to_h               
=> {"a"=>"1", "b"=>"2"}   

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