Question

Should be an easy one and might have over complicated the title somewhat.

I have a variable that contains records:

@record = Records.all

and an array that holds some task_id’s:

@array #has for e.g. [1,2,3]

What i want to do check the task_id column of the list of records in @records to see if they contain any of the numbers in the array. If they do then i want those numbers to be put into another array.

i know this is simple but i keep getting confused along the way as im quite new to ruby syntax.

Answer 1

This should work for you:

@records.map(&:task_id) & @array

This builds the intersection of the two lists (task_ids and array). You can try this example at the console (I hope this helps to clear up how it works):

irb(main):008:0> a =  [1,2,3,4]
=> [1, 2, 3, 4]
irb(main):009:0> b = [3,4,5,6]
=> [3, 4, 5, 6]
irb(main):010:0> a & b
=> [3, 4]