Add script for analyzing date ranges in PubMed files

scripts/date_range_from_pubmed_xml.rb

@@ -0,0 +1,100 @@
+# Given a PubMed abstract index XML file, get the range of years
+# covered by the article citations
+require 'nokogiri'
+
+class CitationParser < Nokogiri::XML::SAX::Document
+
+
+  def initialize(filename)
+    @filename = filename
+  end
+
+  def start_document
+    @text = ''
+    @years = []
+    @in_pub_date = false
+    @capture = false
+  end
+
+  def start_element(element, attrs)
+    case element
+    when 'PubDate'
+      @in_pub_date = true
+    when 'Year'
+      @capture = @in_pub_date
+    end
+  end
+
+  def characters(str)
+    @text += str if @capture
+  end
+
+  def end_element(element)
+    case element
+    when 'Year'
+      if @capture
+        @years << Integer(@text)
+        @text = ''
+        @capture = false
+      end
+    when 'PubDate'
+      @in_pub_date = false
+    end
+  end
+
+  def end_document
+    #puts "Range found: #{@years.min}-#{@years.max} for #{@filename} (avg: #{mean(@years)}, mode: #{mode(@years)}, median: #{median(@years)})"
+    year_report = " ("
+    categories(@years).each do |k, v|
+      year_report += "#{k}: #{v}, "
+    end
+    year_report += ")"
+    puts "Range found: #{@years.min}-#{@years.max} for #{@filename}" + year_report
+  end
+
+  def mean(years)
+    @years.reduce(:+) / @years.count
+  end
+
+  def median(years)
+    sorted = years.sort
+    if years.count % 2 == 0
+      0.5 * (sorted[years.length / 2 - 1] + sorted[years.length / 2])
+    else
+      sorted[years.length / 2]
+    end
+  end
+
+  def mode(years)
+    frequencies = years.reduce(Hash.new(0)) { |h,v| h[v] += 1; h }
+    years.max_by { |y| frequencies[y] }
+  end
+
+  def categories(years)
+    {
+      :early => years.select { |y| y < 1960 }.count,
+      :_1960s => years.select { |y| y >= 1960 && y < 1970 }.count,
+      :_1970s => years.select { |y| y >= 1970 && y < 1980 }.count,
+      :_1980s => years.select { |y| y >= 1980 && y < 1990 }.count,
+      :_1990s => years.select { |y| y >= 1990 && y < 2000 }.count,
+      :_2000s => years.select { |y| y >= 2000 && y < 2010 }.count,
+      :_2010s => years.select { |y| y >= 2010 }.count,
+    }
+  end
+end
+
+
+# Main program
+if ARGV[0]
+  # PRocess the single file specified
+  files = [ARGV[0]]
+else
+  files = Dir['source_files/originals/*']
+end
+puts "\n\nWorking..."
+files.sort.each do |f|
+  parser = Nokogiri::XML::SAX::Parser.new(CitationParser.new(File.basename(f)))
+  #puts "Processing #{f}"
+  parser.parse_file f
+end
+puts "\nDone\n\n"