I have a two dimensional array that looks like this:
TITLETYPE = [['Prof.', '4'],
['Dr.', '3'],
['Mrs.', '2'],
['Ms.', '1'],
['Mr.', '0']]
I need to get the key for value 1 for example (which should be 'Ms.') How should I go about doing that?
TITLETYPE.select{ |x| x[1] == '1' }.first.first
You can use Array's select method to find the row you're looking for. Your rows ar arrays with two elements each (element 0 and element 1), so you need to look for the row in which the second element (element 1) is equal to the value you're looking for (which is the string "1"):
TITLETYPE.select{ |x| x[1] == "1" }
This will return an array with only one row:
[["Ms.", "1"]]
To get the first and only value from that array, use Array's first method, which will return:
["Ms.", "1"]
Then, from that, obtain the first value from the two values with first again:
"Ms."
Actually, sounds like Array#rassoc is perfect for you.
TITLETYPE.rassoc('1')[0] # => 'Ms.'
See the documentation at Ruby-doc.
More naturally, you should keep such information as a hash. If you often want key-to value, and key-to value is unique, then create a hash:
TYTLETYPEHASH = Hash[TYTLETYPE.map(&:reverse)]
and access it:
TYTLETYPEHASH['1'] # => 'Ms.'
or create a hash like:
TYTLETYPEHASH = Hash[TYTLETYPE]
and access it:
TYTLEHASH.key('1') # => 'Ms.'
I had a similar issue, and resolved it by simply using something like this:
<% Array.each do |value| %>
and accessing each element using <%= value[:keyname] %>
i.e.
An array which looks like this (using .inspect)
[{:id=>1, :title=>"ABC"}, {:id=>2, :title=>"XYZ"}]
can become a HTML selection/dropdown box with:
<select name="ClassName[TargetParameter]">
<% Array.each do |value| %>
<option value="<%= value[:id] %>"><%= value[:title] %></option>
<% end %>
</select>
