# Nuby - help with Ruby object references

**URL:** <https://www.ruby-forum.com/t/nuby-help-with-ruby-object-references/54138>\
**Category:** Ruby\
**Created:** [February 24, 2006, 1:36am UTC](https://www.ruby-forum.com/t/nuby-help-with-ruby-object-references/54138 "2006-02-24T01:36:45Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [February 24, 2006, 1:36am UTC](https://www.ruby-forum.com/t/nuby-help-with-ruby-object-references/54138/1 "2006-02-24T01:36:45Z")

</div>

I’m very new to Ruby (as in, just started yesterday). As a learning  
exercise I decided to write a short program that would traverse a  
directory tree and take note of all duplicate files in that tree.

I’m using a hash of arrays to track all references. The key is the  
filename and I push the path as an array to store the value. If I run  
across a filename for which a key already exists in the hash, I do a  
deeper equality check to see if they are really the same file or if  
they are different. The “deeper check” is comparing file sizes.

If they are the same, I push this new path into my array of arrays so  
I can check against it if I find yet another file with that name. If  
they’re different, I push this new path onto a SECOND hash of arrays.

This is where I have trouble. As soon as I push any value into this  
second hash, it takes on the identity of the first hash. I don’t  
understand why because I am not doing any explicit operation to make  
hash1 = hash2. Maybe it’s a side effect of some other operation.  
Anyway, enough talk… the code is below.

I appreciate any and all insight.

cr

— code here —

#!/usr/bin/env ruby

require ‘find’

h = Hash.new { |h,k| h[k] = [] }  
duplicates = Hash.new { |h,k| h[k] = [] }

working\_path = ARGV[0] || ENV[“PWD”]

Find.find(working\_path) do |path|

# if it’s a dir, skip to the next path

if File.directory?(path)  
next  
end  
file = File.basename(path)

# if this key doesn’t exist in the hash, add it

if h.has\_key?(file) == false  
h[file].push([path])  
else # key already exists in hash  
# add file size to hash unless it was already grabbed  
h[file].push([path])  
h[file].each do |subarray|  
subarray[1] = File.size(subarray[0]) unless subarray[1]  
end

```
 # now compare the current file's size to the prior check
 h[file].each do |subarray|
   puts "subarray[0] = #{subarray[0]} and path = #{path}"
   if subarray[0].eql?(path) == false && subarray[1] == File.size

```

(path)  
# add to dupe hash  
puts “DUPLICATE DUPLICATE DUPLICATE DUPLICATE”  
puts “DUP BEFORE h.id = #{h.object\_id} and duplicates.id = #  
{duplicates.object\_id}”  
duplicates[file].push([path]) # at this point “h” and  
“duplicates” refer to the same object!  
puts “DUP AFTER h.id = #{h.object\_id} and duplicates.id = #  
{duplicates.object\_id}”  
end  
end  
end  
end

puts “\n\nThe duplicates are…”  
duplicates.each do |key, value|  
puts “key = #{key}”  
value.each do |a|  
print "#{a[0]} #{a[1]} "  
end  
print “\n”  
end

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [February 24, 2006, 2:57am UTC](https://www.ruby-forum.com/t/nuby-help-with-ruby-object-references/54138/2 "2006-02-24T02:57:57Z")

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unknown wrote:

> I appreciate any and all insight.
> 
> cr
> 
> — code here —
> 
> #!/usr/bin/env ruby
> 
> require ‘find’
> 
> h = Hash.new { |h,k| h[k] = [] }  
> duplicates = Hash.new { |h,k| h[k] = [] }

I am pretty sure this is where the problem is. Blocks  
are closures so the ‘h’ in the second block refers to  
the first Hash. Just change the first variable name  
from ‘h’ to ‘hash’ in the whole file (it is a bit  
clearer anyway) and you should be OK.

> 

E

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [February 24, 2006, 3:55am UTC](https://www.ruby-forum.com/t/nuby-help-with-ruby-object-references/54138/3 "2006-02-24T03:55:42Z")

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On Feb 23, 2006, at 7:58 PM, Eero S. wrote:

> > require ‘find’
> > 
> > h = Hash.new { |h,k| h[k] = [] }  
> > duplicates = Hash.new { |h,k| h[k] = [] }
> 
> I am pretty sure this is where the problem is. Blocks  
> are closures so the ‘h’ in the second block refers to  
> the first Hash. Just change the first variable name  
> from ‘h’ to ‘hash’ in the whole file (it is a bit  
> clearer anyway) and you should be OK.

Okay, I did as you suggested and it works now. But…

I thought the scoping rules were different. I just checked pages 105  
and 106 in the Pickaxe book to confirm the rules and they match up  
with what you said. I’m clear on this now.

Thanks very much…

cr