Delete duplicate records from a 2 dimensional array in rails

rubyonrails-talk
1

Hello,

I am trying to insert elements into an array like this…

@mem = []
@tran = Transport.find_all_by_month_and_vehicle(date,vehicle)
tran.each do |t|
  @mem << [Student.find_by_id(t.mem_id), t.transport_date, vehicle.no] if t.mem_type=="Student"
  @mem << [Employee.find_by_id(t.mem_id), t.transport_date, vehicle.no] if t.mem_type=="Employee"
end

And in the view page I am looping and displaying it as

@mem.each do |m|
  <tr>
            <td><%= link_to m[0].first_name} %></td>
            <td > <%= m[0].age %></td>
            <td id="date"> m[1] </td>
            <td id="vehicle"> m[2] </td>
  </tr>
<%end%>

But I am getting duplicate entries in the table... So I neeed to remove duplicates and display only unique values.. I tries doing
  @mem << [Student.find_by_id(t.mem_id), t.transport_date, vehicle.no].uniq! if t.mem_type=="Student".. But it is not working.. Please help
2

@tran = Transport.where( date: date, vehicle: vehicle) @mem = @tran.members

Iterate in view

@mem.each do |mem|   mem.name   mem.vehicle

Should work if you have the relations set up. You should go read one or two tutorials about relations and how to set them up.

3

if you really need to do some processing that gets you an array with duplicate entries and then clean the array at the end of it all. try doing something like

@mem = @mem.uniq

you can probably do @mem.uniq! but i’ve had some cases where that didn’t get me the results i wanted.

4

uniq can take a block as well if you wanted to unique similar arrays on a specific element:

@mem.uniq { |mem| mem[1] }

Or even on multiple criteria:

@mem.uniq { |mem| [ mem[1], mem[2] ] }

5

Joel Pearson wrote in post #1121051:

uniq can take a block as well if you wanted to unique similar arrays on a specific element:

@mem.uniq { |mem| mem[1] }

Or even on multiple criteria:

@mem.uniq { |mem| [ mem[1], mem[2] ] }

This was very helpful

Thank you