Question

假设我有一个包含4个字段的CSV文件，

ID,name,pay,age

和大约32,000条记录。

在Ruby中将其粘贴到哈希中的最佳方法是什么？

换句话说，示例记录如下：

{：rec1 =＆gt; {：id =＆gt;“00001”，：name =＆gt; “Bob”，：pay =＆gt; 150，：age =＆gt; 95}}

感谢您的帮助！

Answer 1

您可以使用Excelsior rubygem：

csv = ...
result = Hash.new
counter = 1
Excelsior::Reader.rows(csv) do |row|
   row_hash = result[("rec#{counter}".intern)] = Hash.new

   row.each do |col_name, col_val|
      row_hash[col_name.intern] = col_val
   end
   counter += 1
end

# do something with result...

Answer 2

通常我们希望对Hash键使用:id字段，因为它与数据库表中的主键相同：

{"00001" => {:name => "Bob", :pay => 150, :age => 95 } }

这将创建一个类似的哈希：

require 'ap'

# Pretend this is CSV data...
csv = [
  %w[ id     name  pay age ],
  %w[ 1      bob   150 95  ],
  %w[ 2      fred  151 90  ],
  %w[ 3      sam   140 85  ],
  %w[ 31999  jane  150 95  ]

]

# pull headers from the first record
headers = csv.shift

# drop the first header, which is the ID. We'll use it as the key so we won't need a name for it.
headers.shift

# loop over the remaining records, adding them to a hash
data = csv.inject({}) { |h, row| h[row.shift.rjust(5, '0')] = Hash[headers.zip(row)]; h }
ap data

# >> {
# >>     "00001" => {
# >>         "name" => "bob",
# >>          "pay" => "150",
# >>          "age" => "95"
# >>     },
# >>     "00002" => {
# >>         "name" => "fred",
# >>          "pay" => "151",
# >>          "age" => "90"
# >>     },
# >>     "00003" => {
# >>         "name" => "sam",
# >>          "pay" => "140",
# >>          "age" => "85"
# >>     },
# >>     "31999" => {
# >>         "name" => "jane",
# >>          "pay" => "150",
# >>          "age" => "95"
# >>     }
# >> }

Answer 3

查看Ruby Gem smarter_csv，它解析CSV文件并返回CSV文件中行的哈希数组。它还可以进行分块，以更有效地处理大型CSV文件，因此您可以将块传递给并行的Resque worker或使用Mongoid或MongoMapper批量创建记录。

它提供了大量有用的选项 - 查看GitHub

上的文档

require 'smarter_csv'
filename = '/tmp/input.csv'
array = SmarterCSV.process(filename)

=>

[ {:id=> 1, :name => "Bob", :pay => 150, :age => 95 } ,
 ...
]

另见：

Answer 4

Hash[*CSV.read(filename, :headers => true).flat_map.with_index{|r,i| ["rec#{i+1}", r.to_hash]}]

将CSV数据存储在Ruby哈希中

4 个答案: