如果第一行后跟一个空行，Ruby CSV不会找到文件头 [英] Ruby CSV doesn't find file headers if first line is followed by an empty one

问题描述

我遇到了一个奇怪的问题，我的脚本不能在一些CSV文件上工作。问题是以下，我需要访问列名称（文件头）来正确处理文件。我一直在使用以下（测试）代码列出标题：

I have encountered an odd issue where my script wouldn't work on some CSV files. Problem is the following, I need to access the column names (file headers) to properly process the file. I've been using the following (test) code to list the headers :

CSV file = CSV.read(argument, :headers => true)
if file.headers() == nil
    puts "According to the doc : Headers will not be used"
elsif file.headers() == true
    puts "According to the doc : Headers will be used, but not read yet"
else
    puts "Headers were read, this is an array : #{file.headers.to_s}"
end

现在，应用于第一个csv：

Now, applied to the first csv :

key,fr
edit,Éditer
close,Fermer

我得到：

Headers were read, this is an array : ["key", "fr"]

但是，如果我知道在标题和内容之间添加一个空行如下：

But, if I know add an empty line between the headers and the content itself, like so :

key,fr

edit,Éditer
close,Fermer

它不再工作：

Headers were read, this is an array : []

这让我很生气。这是预期的行为吗？有什么我能做的吗？我一直在阅读ruby CSV文件，但找不到任何东西。
它可能是一些csv文件规格我不知道？
在ruby 1.9.3和2.1.1上测试

This baffles me. Is this expected behavior ? Is there anything I can do about it ? I've been reading the ruby CSV doc but cannot find anything. Could it be some csv file specs I don't know about ? Tested on ruby 1.9.3 and 2.1.1

推荐答案

添加选项：skip_blanks =>

Add the option :skip_blanks => true when you are reading the CSV file.

file = CSV.read(path, :headers => true,:skip_blanks => true)

此选项：skip_blanks => true ，将跳过所有这样的空行，如果你有任何现在，你会得到正常的输出。

This option :skip_blanks => true, will skip all such blank lines if any present like you are having, and you will get the normal output.

这里是我的尝试同样：

require 'csv'

content = <<_
key,fr

edit,Éditer
close,Fermer
_

File.write('test',content)

file = CSV.read('test', :headers => true,:skip_blanks => true)
if file.headers() == nil
    puts "According to the doc : Headers will not be used"
elsif file.headers() == true
    puts "According to the doc : Headers will be used, but not read yet"
else
    puts "Headers were read, this is an array : #{file.headers.to_s}"
end
# >> Headers were read, this is an array : ["key", "fr"]

你说，我也同意你，下面一个：

Working correctly as you said, and I also agreed with you, below one :

require 'csv'

content = <<_
key,fr
edit,Éditer
close,Fermer
_

File.write('test',content)

file = CSV.read('test', :headers => true)
file.headers # => ["key", "fr"]
file.to_a # => [["key", "fr"], ["edit", "Éditer"], ["close", "Fermer"]]

当您设置：headers => true 是CSV数据的第一行，您将会看到标题。考虑到这个定义，上面的内容很好。但下面一个矛盾：

When you set :headers => true, the first row of the CSV data, you have will be tread as header. With this definition in mind, The above goes well. But the below one contradicts :

require 'csv'

File.write('test',content)

file = CSV.read('test', :headers => true)
file.headers # => ["key", "fr"]
file.to_a # => [["key", "fr"], ["edit", "Éditer"], ["close", "Fermer"]]

content = <<_
key,fr

edit,Éditer
close,Fermer
_

File.write('test1',content)

file = CSV.read('test1', :headers => true)
file.headers # => []  # <~~~~~~~~~~~ Is this a bug ?
file.to_a # => [[], [], ["edit", "Éditer"], ["close", "Fermer"]]

b $ b

file.headers 给出一个空数组 [] ，你可以看到， strong> 0 ^th 输出 file.to_a 的索引也是一个空数组（ [] ）。但它似乎是一个错误。因此，我提出了 。

file.headers gives an empty array [], as you can see that in the 0^th index of the output of file.to_a is also an empty array([]). But it seems to a bug. Thus I raised the issue.

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