From: Robert Klemme <shortcutter@...>
Date: 2010-03-13T19:00:06+09:00
Subject: Re: Dir.glob problem

On 03/13/2010 03:15 AM, Michael W Ryder wrote:
> Joel VanderWerf wrote:
>> Michael W Ryder wrote:
>>> Michael W Ryder wrote:
>>>> David Vlad wrote:
>>>>> In the program Im making I need to read some wma files into a variable
>>>>> and I did like this:
>>>>>
>>>>> songs = Dir.glob("C:\\Users\\Public\\Music\\Sample Music\\*.wma")
>>>>>
>>>>> Note that this is NOT the wrong directory, I've copy pasted it from 
>>>>> the
>>>>> map itself and also the files are wma and nothing else. My programming
>>>>> teacher has no idea why this dosnt work and the other ppl I've talked
>>>>> with dosnt know either. Most said something like "aside from a simple
>>>>> mistake like wrong directory/extension, I don't know what could be 
>>>>> going
>>>>> wrong." So now this forum is my last resort, why on earth dosnt this
>>>>> work?!
>>>> The only way I could get it to work is to use the example at 
>>>> http://ruby-doc.org/core/classes/Dir.html and create a directory 
>>>> variable such as: lfiles=Files.join("C:", "Users", "Public", 
>>>> "Music", "Sample Music", "*.wma") and then use a=Dir.glob(lfiles).
>>>> The only problem with that approach is that the entire path is added 
>>>> to each file.  I don't know if this is a concern or not.
>>> Further experimenting found two other solutions.  The first is to use:
>>> a=Dir.glob("C:/Users/Public/Music/Sample Music/*.wma") which has the 
>>> same "problem" as my first solution.
>>> A better solution may be to use Dir.chdir to change to the directory 
>>> and then use Dir.glob to extract the file names.  This has the 
>>> advantage of not including the path in front of each file name.
>>
>> chdir is not thread safe, it changes the pwd which is global to the 
>> process. Here's an alternative:
>>
>> d = Dir.new("/tmp") # use fwd slashes even on windows
>> d.grep(/\.wma$/)
>>
>> This should give you an array of filenames in the dir.
>>
> 
> Is there a way to expand this to include subdirectories like .glob 
> allows?  .grep doesn't appear to work on the string created by File.join.

If you want to do globbing, include subdirectories and want to have 
relative paths. I would look at Pathname.  You can, for example, 
generate relative paths via #relative_path_from:

irb(main):025:0> 
Pathname("/var/log/foo").relative_path_from(Pathname("/var"))
=> #<Pathname:log/foo>
irb(main):026:0> 
Pathname("/var/log/foo").relative_path_from(Pathname("/var")).to_s
=> "log/foo"

Pathname has also a method #find which yields Pathname instances to the 
block and can be used for things like this.

Kind regards

	robert

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