Solution for thread "array.map! + delete_if possible ?" in ruby-talk

array.rb

require 'pp'

arr = <<TEXT.scan(/^.*$/)
1201 0 "userid" 1202 0 "lname" 1203 0 "mname" 1204 0 "lname" 1217 0 "password"

4 0 emailaddress
1201 0 "userid" 1202 0 "lname" 1203 0 "mname" 1204 0 "lname" 1217 0 "password"

1201 0 "userid" 1202 0 "lname" 1203 0 "mname" 1204 0 "lname" 1217 0 "password"
TEXT

pp arr

# Solution

# 1. extract fields and create records as Hashes
#    record field positions

fields = {} # record field positions
result = [{}] # resulting records

arr.each do |line|
  line.scan /(\d+)\s+\d+\s+(?:"([^"]*)"|([a-z]\S*))/i do
    # extract data
    field = Integer($1)
    text = $2 || $3

    # record field order
    fields[field] ||= fields.size

    if result.last[field]
      # record complete => add new one
      result << {field => text}
    else
      # record incomplete => set field
      result.last[field] = text
    end
  end
end

pp result

# 2. convert the fields list to an ordered array

fields = fields.sort_by {|k,i| i}.map {|k,i| k}

# 3. convert records to strings

result.map! {|a| fields.map {|k| a[k]}.uniq.join '::'}

pp result