From: Robert Klemme <shortcutter@...>
Date: 2011-12-09T18:18:02+09:00
Subject: Re: reading from file without end-of-lines

On Fri, Dec 9, 2011 at 9:58 AM, Gavin Sinclair <gsinclair@gmail.com> wrote:
>> i'm trying to read a few text values from single file:
>>
>>  if File.exists?(file)
>>      File.open(file, 'r+') do |f|
>>        value1 = f.gets.strip
>>        value2 = f.gets.strip
>>        value3 = f.gets.strip
>>        value4 = f.gets.strip
>>      end
>>    end
>>
>> each value is stored in separate line and 'strip' above is used only to
>> get rid of end-of-line characters. is there any easier way to do the same?

You could start by not defining individual variables with indexed
names but using an array.

> I tend to strip out all such characters at once, before operating on any line.
>
>  File.readlines(file).map { |line| line.strip }.each do |line|
>    ...
>  end
>
> In your case, I guess that would be
>
>  lines = File.readlines(file).map { |line| line.strip }
>  value1 = lines.shift
>  value2 = lines.shift
>  # etc.
>  # or
>  v1, v2, v3, v4 = lines.shift(4)

Executing File.readlines completely is inefficient if the file is
large and only the first four lines are needed.

One could do

values = File.open(file) do |f|
  f.first(4).map! &:strip!
end

Or even shorter

values = File.foreach("cl").first(4).map! &:strip!

If there are proper names for variables one can do

name, street, zip, city = File.foreach("cl").first(4).map! &:strip!

;-)

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
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