我想使用ruby将.json文件转换为.csv文件。请帮助我这样做。
还提出任何工具来实现这一目标。
答案 0 :(得分：24)
尝试这样的事情：
require 'csv'
require 'json'
csv_string = CSV.generate do |csv|
JSON.parse(File.open("foo.json").read).each do |hash|
csv << hash.values
end
end
puts csv_string
答案 1 :(得分：9)
实际写入文件...
require 'csv'
require 'json'
CSV.open("your_csv.csv", "w") do |csv| #open new file for write
JSON.parse(File.open("your_json.json").read).each do |hash| #open json to parse
csv << hash.values #write value to file
end
end
答案 2 :(得分：5)
我认为在ruby中将JSON转换为CSV的简单方法是使用json2csv ruby gem。
PS：我可能有偏见，因为我是这个人的作者。运行命令
json2csv convert data/sample.json
输入文件
在这种特殊情况下，它将转换为以下json：
cat data/sample.json
{
"12345": {
"Firstname": "Joe",
"Lastname": "Doe",
"Address": {
"Street": "#2140 Taylor Street, 94133",
"City": "San Francisco",
"Details": {
"note": "Pool available"
}
}
},
"45678": {
"Firstname": "Jack",
"Lastname": "Plumber",
"Address": {
"Street": "#111 Sutter St, 94104",
"City": "San Francisco",
"Details": {
"note": "Korean Deli near to main entrance"
}
}
}
<强>输出
cat data/sample.json.csv
id,Firstname,Lastname,Address.Street,Address.City,Address.Details.note
12345,Joe,Doe,"#2140 Taylor Street, 94133",San Francisco,Pool available
45678,Jack,Plumber,"#111 Sutter St, 94104",San Francisco,Korean Deli near to main entrance
答案 3 :(得分：4)
基于@Alex's answer，但添加 csv标头和示例测试。
# utils.rb
require "csv"
module Utils
def self.array_of_hashes_to_csv(array_of_hashes)
CSV.generate do |csv|
csv << array_of_hashes.first.keys
array_of_hashes.each { |hash| csv << hash.values }
end
end
end
# utils_test.rb
class UtilsTest < MiniTest::Unit::TestCase
def test_array_of_hashes_to_csv
array_of_hashes = [
{ :key1 => "value1", :key2 => "value2" },
{ :key1 => "value3", :key2 => "value4" }
]
expected_result = "key1,key2\nvalue1,value2\nvalue3,value4\n"
assert_equal(expected_result, Utils.array_of_hashes_to_csv(array_of_hashes))
end
end
答案 4 :(得分：3)
修改：
下面描述的此功能现在以gem提供。使用gem install json_converter安装后，可以使用以下代码段从有效的JSON字符串或对象生成CSV：
require 'json_converter'
json_converter= JsonConverter.new
# Assume json is a valid JSON string or object
csv = json_converter.generate_csv json
原始答案：
如果您的JSON数据相对简单（没有嵌套或数组），Alex的答案可能是解决此问题的最简洁方法。
但是，如果你做需要考虑数组和嵌套对象，我试图将web version这样的转换器移植到ruby。它可以找到here。处理数据实际重组的方法是array_from和flatten。
array_from方法尝试识别＆＃34;行＆＃34;对于给定的数据集，数据看起来像。它并不完美，您可能希望针对不同的数据集调整此部分。
# Attempt to identify what a "row" should look like
def array_from(json)
queue, next_item = [], json
while !next_item.nil?
return next_item if next_item.is_a? Array
if next_item.is_a? Hash
next_item.each do |k, v|
queue.push next_item[k]
end
end
next_item = queue.shift
end
return [json]
end
flatten方法以递归方式迭代JSON对象，并生成表示标题和值的对象。如果对象是嵌套的，则其列的标题将以其父键为前缀，由/字符分隔。
# The path argument is used to construct header columns for nested elements
def flatten(object, path='')
scalars = [String, Integer, Fixnum, FalseClass, TrueClass]
columns = {}
if [Hash, Array].include? object.class
object.each do |k, v|
new_columns = flatten(v, "#{path}#{k}/") if object.class == Hash
new_columns = flatten(k, "#{path}#{k}/") if object.class == Array
columns = columns.merge new_columns
end
return columns
elsif scalars.include? object.class
# Remove trailing slash from path
end_path = path[0, path.length - 1]
columns[end_path] = object
return columns
else
return {}
end
end
如果原始JSON中有任何null值，则在尝试转换之前，您需要将这些值转换为nil以外的其他值 - 您通常会以如果你不这样，那么行不均匀。 nils_to_strings方法处理：
# Recursively convert all nil values of a hash to empty strings
def nils_to_strings(hash)
hash.each_with_object({}) do |(k,v), object|
case v
when Hash
object[k] = nils_to_strings v
when nil
object[k] = ''
else
object[k] = v
end
end
end
这是一个如何使用它的简短示例：
json = JSON.parse(File.open('in.json').read)
in_array = array_from json
in_array.map! { |x| nils_to_strings x }
out_array = []
in_array.each do |row|
out_array[out_array.length] = flatten row
end
headers_written = false
CSV.open('out.csv', 'w') do |csv|
out_array.each do |row|
csv << row.keys && headers_written = true if headers_written === false
csv << row.values
end
end
最后，这里有一些输入/输出示例：
输入：
{
"Forms": [
{
"Form": {
"id": "x",
"version_id": "x",
"name": "x",
"category": "",
"subcategory": null,
"is_template": null,
"moderation_status": "x",
"display_status": "x",
"use_ssl": "x",
"modified": "x",
"Aggregate_metadata": {
"id": "x",
"response_count": "x",
"submitted_count": "x",
"saved_count": "x",
"unread_count": "x",
"dropout_rate": "x",
"average_completion_time": null,
"is_uptodate": "x"
}
},
"User": {
"username": "somedude@example.com"
}
},
{
"Form": {
"id": "x",
"version_id": "x",
"name": "x",
"category": "",
"subcategory": null,
"is_template": null,
"moderation_status": "x",
"display_status": "x",
"use_ssl": "x",
"modified": "x",
"Aggregate_metadata": {
"id": "x",
"response_count": "x",
"submitted_count": "x",
"saved_count": "x",
"unread_count": "x",
"dropout_rate": "x",
"average_completion_time": null,
"is_uptodate": "x"
}
},
"User": {
"username": "somedude@example.com"
}
}
]
}
输出：
Form/id,Form/version_id,Form/name,Form/category,Form/subcategory,Form/is_template,Form/moderation_status,Form/display_status,Form/use_ssl,Form/modified,Form/Aggregate_metadata/id,Form/Aggregate_metadata/response_count,Form/Aggregate_metadata/submitted_count,Form/Aggregate_metadata/saved_count,Form/Aggregate_metadata/unread_count,Form/Aggregate_metadata/dropout_rate,Form/Aggregate_metadata/average_completion_time,Form/Aggregate_metadata/is_uptodate,User/username
x,x,x,"","","",x,x,x,x,x,x,x,x,x,x,"",x,somedude@example.com
x,x,x,"","","",x,x,x,x,x,x,x,x,x,x,"",x,somedude@example.com
答案 5 :(得分：1)
要从json转换为csv的Ruby代码。
通过将数组转换为双引号字符串来处理数组。
#json-to-csv.rb
require 'json'
require 'csv'
file = File.read('./input.json')
hash = JSON.parse(file)
CSV.open('./output.csv', 'w') do |csv|
headers = hash.first.keys
csv << headers
hash.each do |item|
values = item.values
printable_values = Array.new
values.each do |value|
printable_values << value.to_s.gsub(/\[|\]/,'').gsub(/"/,'\'')
end
csv << printable_values
end
end
答案 6 :(得分：0)
这是句柄标题＆amp;嵌套的json。
require 'csv'
require 'json'
@headers = []
file = File.open('file.json')
JSON.parse(file.read).each do |h|
h.keys.each do |key|
@headers << key
end
end
uniq_headers = @headers.uniq
file = File.open('file.json')
finalrow = []
JSON.parse(file.read).each do |h|
final = {}
@headers.each do |key2|
final[key2] = h[key2]
end
finalrow << final
end
CSV.open('output.csv' , 'w') do |csv|
csv << uniq_headers
finalrow.each do |deal|
csv << deal.values
end
end