Rails迁移，使用split添加新列-split（）不起作用

Question

I'm trying to add a max and min column to my model, based on a delimited string from another column:

804025|1356906|2246774

So the min should be: 804025 , and the max should be: 2246774

I'm using this migration script:

def change
    add_column :mer14s, :rmax, :int
    add_column :mer14s, :rmin, :int
    Mer14.all.each do |mer|
        nums_a = []
        if mer.leading
            nums_a += mer.leading.split('|').map(&:to_i)
            puts mer.leading
            puts nums_a
        end
        if mer.lagging
            nums_a += mer.lagging.split('|').map(&:to_i)
        end
        if nums_a.length > 0
            mer.update_attributes(:rmax => nums_a.max)
            mer.update_attributes(:rmin => nums_a.min)
        end
    end
  end

However, the split('|') only returns the first element.

puts leading
puts num_a 

Output:

804025|1356906|2246774
804025

I've confirmed it works in the rails console by using:

Mer14.all[18].leading.split('|').map(&:to_i)

Output [1189919, 3219748, 4010566]

But it doesn't work in my migration file, nor does it work elsewhere (eg my models). Can anyone tell me why this is?

Answer 1

For some reason the split method didn't enjoy using a string inside rails. Instead a regex was used, so the original:

nums_a += mer.leading.split('|').map(&:to_i)

Becomes:

nums_a += mer.leading.split(/\\|/).map(&:to_i)

Answer 2

This works for me:

a = "804025|1356906|2246774"
a.split('|').map(&:to_i).max
=> 2246774
a.split('|').map(&:to_i).min
=> 804025