Glob on a dir object


#1

Hi

I am a Ruby newbie and having fun learning it so far…Can anyone help
me as to why this does not work?

Why does not glob method work on a Directory object created or am I
not using the OO constrcuts the right way?

irb(main):001:0> dh = Dir.new("/tmp/zz")
=> #Dir:0x64018
irb(main):002:0> dh.each { |f| puts “Has file #{f}” }
Has file .
Has file …
Has file a
Has file aa
Has file b
Has file c
Has file d
=> #Dir:0x64018

irb(main):003:0> arr = dh.glob(“a?”)
NoMethodError: undefined method `glob’ for #Dir:0x64018
from (irb):3

Thanks!
VS


#2

On 4/24/07, ruby newbie removed_email_address@domain.invalid wrote:

Hi

I am a Ruby newbie and having fun learning it so far…Can anyone help
me as to why this does not work?

Why does not glob method work on a Directory object created or am I
not using the OO constrcuts the right way?

Right.

The glob method is only available on the Dir class. Observe:
C:>ri Dir#glob
Nothing known about Dir#glob

C:>ri Dir::glob
-------------------------------------------------------------- Dir::glob
Dir.glob( string, [flags] ) => array
Dir.glob( string, [flags] ) {| filename | block } => nil

 Returns the filenames found by expanding the pattern given in
 _string_, either as an _array_ or as parameters to the block. Note
 that this pattern is not a regexp (it's closer to a shell glob).
 See +File::fnmatch+ for the meaning of the _flags_ parameter.

hth,
-Harold


#3

ahh, That makes sense now. I get :: and # syntax that I saw in
Pragmatic programmer’s guide .Thank you Harold & Jesse.


#4

On Monday 23 April 2007 19:29, ruby newbie wrote:

Why does not glob method work on a Directory object created or am I
not using the OO constrcuts the right way?

glob is a class method of Dir, not an instance method.

irb(main):002:0> Dir::glob(’/tmp/zz/a?’)
=> ["/tmp/zz/aa"]

If you run ‘ri Dir’ from the command-line, you can see glob appears
under
‘Class methods’. Running ‘ri Dir::glob’ gives example usage. glob
returns
an array of strings, but if you want Files, you can do this:

irb(main):007:0> Dir::glob(’/tmp/zz/a*’).map { |f| File.new f }
=> [#<File:/tmp/zz/a>, #<File:/tmp/zz/aa>]

(though perhaps there’s a better way; I haven’t done too much with
Dir/File
myself…)


#5

Hi,

Indeed, “glob” is a classe methods of “Dir” but since Dir is a child
of Enumerable module, you have access to all instance methods of
Enumerable module like, for instance : grep.

So :
dh.grep(/^a?/)

…should play the same role as the glob class method