匹配Ruby中多个数组的相应对象索引值

Question

I have three arrays =

name = ["sample","test","sample"]
date = ["September","October","November"]
score = [10,20,30]

I want to loop through each object in name and return the index value of every object that is equal to sample . The idea is to then take that index and return the corresponding objects in date and score . This is how I'm doing it currently:

new_name_array = []
new_date_array = []
new_score_array = []
count = 0
name.each do |x|
  if x == 'sample'
    new_name_array << x
    new_date_array << date.index[count]
    new_score_aray << score.index[count]

    count += 1
  else
    count += 1
    next
  end
end

Then I have three new arrays that have only the values I need, and I can base the rest of my script off of those arrays.

I know there's a better way to do this - There's no way this is the most efficient way. Can someone provide some suggestions to write the above in a cleaner way?

Sidenote:

Is there a way to pull the integer value for x in the loop instead of using the count += 1 ?

Answer 1

How about something like

name.zip(date, score).select { |x| x.first == 'sample' }

You'll get back an array of three-element arrays:

[["sample", "September", 10], ["sample", "November", 30]]

Also, if you need the index of an element when you're iterating, you usually use each_with_index .

Answer 2

Here is one way :

name = ["sample","test","sample"]
date = ["September","October","November"]
score = [10,20,30]

indexes = name.map.with_index{|e,i| i if e=='sample'}.compact
indexes # >> [0, 2]
new_date_array = date.values_at(*indexes) # >> ["September", "November"]
new_score_array = score.values_at(*indexes) # >> [10, 30]