English 中文(简体)
如何简化这一铁路法——从档案中排出第一线,并按每个要素分类。
原标题:How to simplify this Rails code -- gets first line from file, parses it and downcases each element
fields = CSV.parse(File.open(filename).first)[0]
fields.each_with_index do |field, i|
  fields[i] = field.downcase
end

我想从一线走到第一线,把它归为CSV,使每个要素降低。

这对我来说似乎太多余。 任何建议?

最佳回答

如果希望:

fields.map!(&:downcase)

甚至:

fields = CSV.parse(File.open(filename).first)[0].map(&:downcase)

我认为,你再留下一个档案处理 there死问题,这样你可能想尝试像:

fields = []
File.open(filename) do |f|
  fields = CSV.parse(f.readline)[0].map(&:downcase)
end
问题回答

我不认为你有什么错误,但可以说:

fields = CSV.parse(File.open(filename,  r ).first).first.map(&:downcase)

或者,你可以比较容易阅读某些方法:

def first_line_of(filename)
  File.open(filename,  r ).first
end

def csv_to_array(string)
  CSV.parse(string).first
end

def downcase(a)
  a.map(&:downcase)
end      

fields = downcase csv_to_array first_line_of filename




相关问题
rails collection_select vs. select

collection_select and select Rails helpers: Which one should I use? I can t see a difference in both ways. Both helpers take a collection and generates options tags inside a select tag. Is there a ...

SSL slowness in EC2

We ve deployed our rails app to EC2. In our setup, we have two proxies on small instances behind round-robin DNS. These run nginx load balancers for a dynamically growing and shrinking farm of web ...

Auth-code with A-Za-z0-9 to use in an URL parameter

As part of a web application I need an auth-code to pass as a URL parameter. I am currently using (in Rails) : Digest::SHA1.hexdigest((object_id + rand(255)).to_s) Which provides long strings like : ...

RubyCAS-Client question: Rails

I ve installed RubyCAS-Client version 2.1.0 as a plugin within a rails app. It s working, but I d like to remove the ?ticket= in the url. Is this possible?

activerecord has_many :through find with one sql call

I have a these 3 models: class User < ActiveRecord::Base has_many :permissions, :dependent => :destroy has_many :roles, :through => :permissions end class Permission < ActiveRecord::...

Ordering a hash to xml: Rails

I m building an xml document from a hash. The xml attributes need to be in order. How can this be accomplished? hash.to_xml

Text Editor for Ruby-on-Rails

guys which text editor is good for Rubyonrails? i m using Windows and i was using E-Texteditor but its not free n its expired now can anyone plese tell me any free texteditor? n which one is best an ...

How to get SQL queries for each user where env is production

I’m developing an application dedicated to generate statistical reports, I would like that user after saving their stat report they save sql queries too. To do that I wrote the following module: ...

热门标签