2

我创建了一个关于我的 eshop 的 CSV 文件，其中包含具有不同 SKU 的多个项目。一些 SKU 出现多次，因为它们可以属于多个类别（但对于给定的 SKU，标题和价格将始终相同）。例子：

SKU,Title,Category,Price    
001,Soap,Bathroom,0.5    
001,Soap,Kitchen,0.5
002,Water,Kitchen,0.4
002,Water,Garage,0.4
003,Juice,Kitchen,0.8

我现在希望从该文件创建另一个没有重复 SKU 的 CSV 文件，并聚合“类别”属性，如下所示：

SKU,Title,Category,Price
001,Soap,Bathroom/Kitchen,0.5    
002,Water,Kitchen/Garage,0.4
003,Juice,Kitchen,0.8

我怎样才能做到这一点？

4

2 回答 2

1

我了解您希望读取 CSV 文件，对数据执行一些操作，然后将结果写入新的 CSV 文件。您可以按如下方式进行。

代码

require 'csv'

def convert(csv_file_in, csv_file_out, group_field, aggregate_field)
  csv = CSV.read(FNameIn, headers: true)
  headers = csv.headers
  arr = csv.group_by { |row| row[group_field] }.
            map do |_,a|
              headers.map { |h| h==aggregate_field ?
                (a.map { |row| row[aggregate_field] }.join('/')) : a.first[h] }
            end
  CSV.open(FNameOut, "wb") do |csv|
    csv << headers
    arr.each { |row| csv << row }
  end
end

例子

让我们使用以下数据创建一个 CSV 文件：

s =<<_
SKU,Title,Category,Price
001,Soap,Bathroom,0.5
001,Soap,Kitchen,0.5
002,Water,Kitchen,0.4
002,Water,Garage,0.4
003,Juice,Kitchen,0.8
_


FNameIn  = 'testin.csv'
FNameOut = 'testout.csv'

IO.write(FNameIn, s)
  #=> 135

现在使用这些值执行该方法：

convert(FNameIn, FNameOut, "SKU", "Category")

并确认FNameOut写入正确：

puts IO.read(FNameOut)
SKU,Title,Category,Price
001,Soap,Bathroom/Kitchen,0.5
002,Water,Kitchen/Garage,0.4
003,Juice,Kitchen,0.8

解释

步骤如下：

csv_file_in = FNameIn
csv_file_out = FNameOut
group_field = "SKU"
aggregate_field = "Category"
csv = CSV.read(FNameIn, headers: true)

请参阅CSV::read。

headers = csv.headers
  #=> ["SKU", "Title", "Category", "Price"] 
h = csv.group_by { |row| row[group_field] }
  #=> {"001"=>[
         #<CSV::Row "SKU":"001" "Title":"Soap" "Category":"Bathroom" "Price":"0.5">,
  #      #<CSV::Row "SKU":"001" "Title":"Soap" "Category":"Kitchen" "Price":"0.5">
  #    ],
  #    "002"=>[
  #      #<CSV::Row "SKU":"002" "Title":"Water" "Category":"Kitchen" "Price":"0.4">,
  #      #<CSV::Row "SKU":"002" "Title":"Water" "Category":"Garage" "Price":"0.4">
  #    ],
  #    "003"=>[
  #      #<CSV::Row "SKU":"003" "Title":"Juice" "Category":"Kitchen" "Price":"0.8">
  #    ]
  #   } 
arr = h.map do |_,a|
        headers.map { |h| h==aggregate_field ?
          (a.map { |row| row[aggregate_field] }.join('/')) : a.first[h] }
      end
   #=> [["001", "Soap", "Bathroom/Kitchen", "0.5"],
   #    ["002", "Water", "Kitchen/Garage", "0.4"],
   #    ["003", "Juice", "Kitchen", "0.8"]]

请参阅CSV#headers和Enumerable#group_by，这是一种常用的方法。最后，编写输出文件：

CSV.open(FNameOut, "wb") do |csv|
  csv << headers
  arr.each { |row| csv << row }
end

请参阅CSV::open。现在让我们回到 的计算arr。这很容易通过插入一些puts语句并执行代码来解释。

arr = h.map do |_,a|
          puts "  _=#{_}"
          puts "  a=#{a}"
          headers.map do |h|
            puts "    header=#{h}"
            if h==aggregate_field
              a.map { |row| row[aggregate_field] }.join('/')
            else
              a.first[h]
            end.
            tap { |s| puts "    mapped to #{s}" }
          end
        end

请参阅Object#tap。显示以下内容。

  _=001
  a=[#<CSV::Row "SKU":"001" "Title":"Soap" "Category":"Bathroom" "Price":"0.5">,
     #<CSV::Row "SKU":"001" "Title":"Soap" "Category":"Kitchen" "Price":"0.5">]
    header=SKU
    mapped to 001
    header=Title
    mapped to Soap
    header=Category
    mapped to Bathroom/Kitchen
    header=Price
    mapped to 0.5


  _=002
  a=[#<CSV::Row "SKU":"002" "Title":"Water" "Category":"Kitchen" "Price":"0.4">,
     #<CSV::Row "SKU":"002" "Title":"Water" "Category":"Garage" "Price":"0.4">]
    header=SKU
    mapped to 002
    header=Title
    mapped to Water
    header=Category
    mapped to Kitchen/Garage
    header=Price
    mapped to 0.4


  _=003
  a=[#<CSV::Row "SKU":"003" "Title":"Juice" "Category":"Kitchen" "Price":"0.8">]
    header=SKU
    mapped to 003
    header=Title
    mapped to Juice
    header=Category
    mapped to Kitchen
    header=Price
    mapped to 0.8
于 2019-08-05T23:13:27.320 回答
0

似乎为了使这个正确，我们必须假设 SKU 编号和价格始终相同。由于您知道要在其间合并数据的唯一关键Category是如何做到这一点。

假设这是您的 test.csv，路径与 ruby​​ 脚本相同：

# test.csv
SKU,Title,Category,Price
001,Soap,Bathroom,0.5
001,Soap,Kitchen,0.5
002,Water,Kitchen,0.4
002,Water,Garage,0.4
003,Juice,Kitchen,0.8

test.csv与您的文件位于同一目录中的 Ruby 脚本

# fix_csv.rb
require 'csv'
rows = CSV.read 'test.csv', :headers => true
skews = rows.group_by{|row| row['SKU']}.keys.uniq
values = rows.group_by{|row| row['SKU']}

merged = skews.map do |key|
  group = values.select{|k,v| k == key}.values.flatten.map(&:to_h)
  category = group.map{|k,v| k['Category']}.join('/')
  new_data = group[0]
  new_data['Category'] = category
  new_data
end

CSV.open('merged_data.csv', 'w') do |csv|
  csv << merged.first.keys # writes the header row
  merged.each do |hash|
    csv << hash.values
  end
end

puts 'see contents of merged_data.csv'
于 2019-08-05T22:26:33.480 回答