红宝石：问题解析CSV，并通过行循环

Question

我有一个CSV与一些文件名和日期：

"doc_1.doc", "date1" 
"doc_2.doc", "date2" 
"doc_5.doc", "date5" 

的问题是，有许多空白文件号之间，如：doc_2和doc_5

我正在尝试编写一个脚本来解析CSV，并通过比较每行并填写必要的空白处填充空白处。

例如在这个例子中，它会增加

"doc_3.doc", "date copied from date2" 
"doc_4.doc", "date copied from date2" 

我想因为我想学习的语言写在Ruby中这个脚本，并明确我误解的方式Ruby的循环工作，因为它不是典型的“为“循环在PHP等

在这里，人们经常使用的是到目前为止我的代码，用循环任何帮助自身将不胜感激！

#!/usr/bin/env ruby 

require 'csv' 

# Load file 
csv_fname = './upload-list-docs.csv' 

# Parsing function 
def parse_csv(csv_fname) 
    uploads = [] 
    last_number = 0 

    # Regex to find number in doc_XXX.YYY 
    regex_find_number = /(?<=\_)(.*?)(?=\.)/ 

    csv_content = CSV.read(csv_fname) 

    # Skip header row 
    csv_content.shift 

    csv_content.each do |row| 
     current_number = row[0].match regex_find_number 
     current_date = row[1] 
     last_date = current_date 

     until last_number == current_number do 
      uploads << [last_number, last_date] 
      last_number += 1 
     end 
    end 

    return uploads 
end 

puts parse_csv(csv_fname) 

和一些示例CSV

"file_name","date" 
"doc_1.jpg","2011-05-11 09:16:05.000000000" 
"doc_3.doc","2011-05-11 10:10:36.000000000" 
"doc_4.doc","2011-05-11 10:17:19.000000000" 
"doc_6.doc","2011-05-11 10:58:35.000000000" 
"doc_7.pdf","2011-05-11 11:16:22.000000000" 
"doc_8.pdf","2011-05-11 11:19:29.000000000" 
"doc_9.docx","2011-05-11 11:40:03.000000000" 
"doc_13.pdf","2011-05-11 12:26:32.000000000" 
"doc_14.docx","2011-05-11 12:34:50.000000000" 
"doc_15.doc","2011-05-11 12:40:12.000000000" 
"doc_16.doc","2011-05-11 13:03:11.000000000" 
"doc_17.doc","2011-05-11 13:03:58.000000000" 
"doc_19.pdf","2011-05-11 13:25:07.000000000" 
"doc_20.rtf","2011-05-11 13:34:26.000000000" 
"doc_21.rtf","2011-05-11 13:35:25.000000000" 
"doc_24.doc","2011-05-11 13:49:02.000000000" 
"doc_25.doc","2011-05-11 14:05:04.000000000" 
"doc_26.pdf","2011-05-11 14:18:26.000000000" 
"doc_27.rtf","2011-05-11 14:30:19.000000000" 
"doc_28.doc","2011-05-11 14:33:13.000000000" 
"doc_29.jpg","2011-05-11 15:07:27.000000000" 
"doc_30.doc","2011-05-11 15:22:30.000000000" 
"doc_31.doc","2011-05-11 15:31:07.000000000" 
"doc_34.doc","2011-05-11 15:51:56.000000000" 
"doc_35.doc","2011-05-11 15:55:15.000000000" 
"doc_36.doc","2011-05-11 16:06:46.000000000" 
"doc_38.wps","2011-05-11 16:21:08.000000000" 
"doc_39.doc","2011-05-11 16:30:57.000000000" 
"doc_40.doc","2011-05-11 16:41:55.000000000" 
"doc_43.JPG","2011-05-11 17:03:40.000000000" 
"doc_46.doc","2011-05-11 17:28:13.000000000" 
"doc_51.doc","2011-05-11 17:50:34.000000000" 
"doc_52.doc","2011-05-11 18:03:13.000000000" 
"doc_53.doc","2011-05-11 18:43:48.000000000" 
"doc_54.doc","2011-05-11 18:54:45.000000000" 
"doc_55.doc","2011-05-11 19:31:03.000000000" 
"doc_56.doc","2011-05-11 19:31:23.000000000" 
"doc_57.doc","2011-05-11 20:17:38.000000000" 
"doc_59.jpg","2011-05-11 20:22:55.000000000" 
"doc_61.pdf","2011-05-11 21:14:52.000000000" 

Answer 1

一个面向对象的方法。请注意，我这样做时，我还以为你要充满[doc_X.doc, date]空白，而不是[X, date] - 对此，因为它需要在@file_name更多的正则表达式这种做法是比较合适的。现在这可能有点冗长，但仍然可行，而且非常可读。

require 'csv' 

class Upload 

    attr_reader :file_number, :date 

    def initialize(file_name_or_number, date) 
    @date = date 
    @file_number = if file_name_or_number.is_a?(String) 
        file_name_or_number[/_(\d+)\./, 1].to_i 
        else 
        file_name_or_number 
        end 
    end 

    def to_a 
    [@file_number, @date] 
    end 
end 

class UploadCollection 

    attr_reader :uploads 

    def initialize(input_file) 
    # Slice off all but the first element 
    input_data = CSV.read(input_file)[1..-1] 
    # Create an array of Upload objects and sort by file number 
    @uploads = input_data 
        .map { |row| Upload.new(row[0], row[1]) } 
        .sort_by(&:file_number) 
    end 

    def fill_blanks! 
    # Get the smallest and largest file number 
    # (they're sorted this way, remember) 
    min, max = @uploads.first.file_number, @uploads.last.file_number 
    # Create an array of all numbers between min and max, and 
    # remove those elements already representing a file number 
    missing = (min..max).to_a - @uploads.map(&:file_number) 
    missing.each do |num| 
     # Explaining how this works makes my head ache. Check out the 
     # docs for Array#insert. 
     @uploads.insert(num - 1, Upload.new(num, @uploads[num-2].date)) 
    end 

    # Non-ambiguous return value 
    true 
    end 

    def to_a 
    @uploads.map(&:to_a) 
    end 

    def write_csv(file_path) 
    CSV.open(file_path, 'wb') do |csv| 
     csv << ['file_number', 'date'] # Headers 
     to_a.each { |u| csv << u } 
    end 
    end 
end 

file = 'fnames.csv' 
collection = UploadCollection.new(file) 
collection.fill_blanks! 
puts collection.to_a 
collection.write_csv('out.csv') 

Answer 2

的问题是不与（应该被改变成>=如上面已经所述预留危险==）的循环，但与来自提取的整数正则表达式匹配。

current_number = row[0].match(regex_find_number)[0].to_i 

Answer 3

这里是我会写代码：

require 'csv' 
csv_fname = './upload-list-docs.csv' 

# Create a structure to get some easy methods: 
Myfile = Struct.new(:name,:date){ 
    def number 
    name[/(?<=\_)(.*?)(?=\.)/].to_i 
    end 
    def next_file 
    Myfile.new(name.gsub(/(?<=\_)(.*?)(?=\.)/){|num|num.next}, date) 
    end 
} 

# Read the content and add it to and array: 
content = CSV.read(csv_fname)[1..-1].map{|data| Myfile.new(*data)} 

# Add first entry to an result array: 
result = [content.shift] 

until content.empty? 

# Get new file: 
new_file = content.shift 

# Fill up with new files until we hit next file: 
files_between = new_file.number - result.last.number 
unless files_between == 1 
    (files_between - 1).times do 
    result << result.last.next_file 
    end 
end 

# Add next file: 
result << new_file 

end 

# Map result back to array: 
result.map!(&:to_a)