使用ruby/fastercsv在公共字段上合并CSV文件 [英] merge CSV files on a common field with ruby/fastercsv

问题描述

我有一个主"文件，该文件的列数为:1 2 3 4 5.我还有其他一些文件，其行数少于主文件的行数，每个文件的列数为:1 6.这些文件在第1列字段上匹配，并将第6列添加到主文件中.我看过一些python/UNIX解决方案，但如果合适的话，最好使用ruby/fastercsv.我将不胜感激入门.

I have a 'master' file with a number of columns: 1 2 3 4 5. I have a few other files, with fewer rows than the master file, each with columns: 1 6. I'd like to merge these files matching on the column 1 field and add column 6 to the master. I've seen some python/UNIX solutions but would prefer to use ruby/fastercsv if it's a good fit. I would appreciate any help getting started.

推荐答案

FasterCSV现在是Ruby 1.9中的默认CSV实现.该代码未经测试，但可以正常工作.

FasterCSV is now the default CSV implementation in Ruby 1.9. This code is untested, but should work.

require 'csv'
master = CSV.read('master.csv') # Reads in master
master.each {|each| each.push('')} # Adds another column to all rows
Dir.glob('*.csv').each do |each| #Goes thru all csv files
  next if each == 'master.csv' # skips the master csv file
  file = CSV.read(each) # Reads in each one
  file.each do |line| #Goes thru each line of the file
    temp = master.assoc(line[0]) # Finds the appropriate line in master
    temp[-1] = line[1] if temp #updates last column if line is found
  end
end

csv = CSV.open('output.csv','wb') #opens output csv file for writing
master.each {|each| csv << each} #Goes thru modified master and saves it to file

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