On Thursday, June 26, 2014 10:46:50 PM UTC-7, Hiroyuki Sato wrote:
>
> I wrote find_from_top method.
> I want to simplify this. but It seems work fine.
>
> def traverse_to_leaf(tree,node)
> ret = nil
> return node if tree.empty?
> cur_name = tree.shift
>
> leaf = node.children_dataset.first(:name => cur_name)
> if( leaf )
> ret = traverse_to_leaf(tree,leaf)
> end
> ret
> end
>
> def find_from_top(search_path)
>
> root = FileTree.root
> nodes = search_path.split('/')[1..-1]
> traverse_to_leaf(nodes,root)
>
> end
>
I would recommend an iterative approach:
def find_from_top(search_path)
current = FileTree.root
search_path[1..-1].split('/').each do |name|
break unless current = current.children_dataset.first(:name=>name)
end
current
end
I didn't actually test that, but hopefully it or something similar works.
> An approach using joins:
>>
>> Node.join(:nodes___n1, :parent_id=>:id).
>> join(:nodes___n2, :parent_id=>:id).
>> first(:nodes__name=>'a', :n1__name=>'b', :n2__name=>'c')
>>
>
> joins approach seems good.
> But I'm not sure how to add multiple path dynamically.
> I'll check it.
>
It actually looks very similar to the code above:
def find_from_top_join(search_path)
ds = FileTree.roots_dataset
search_path[1..-1].split('/').each_with_index do |name, i|
ds = ds.join(:file_trees.as("n#{i}"), :parent_id=>:id, :name=>name)
end
ds.first
end
Again, not tested, but hopefully it or something similar works.
Thanks,
Jeremy
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