Quickly,
# First, I'd want a naked struct that will be populated by the data I
actually have.
# To convert your @levels array into this structure, I threw this together:
def naked_tree levels = [], i = 0
o = {}
levels[i].each do |key|
o[key] = naked_tree level, i + 1
end unless i >= levels.size
o = nil if i >= levels.size
o
end
# Kind of weird, but okay...
# Then you can just merge your stuff in recursively.
def merge_hashes unpopulated, populated
o = {}
unpopulated.each do |key, value|
o[key] = merge_hashes(value, (populated.nil? ? nil : populated[key]))
end if unpopulated.kind_of?(Hash)
o = populated unless unpopulated.kind_of?(Hash)
o
end
merge_hashes(naked_tree(@levels), orig_hash)
On 10/18/06, David Turnbull <[EMAIL PROTECTED]> wrote:
Sounds like you're trying to build a class to vend a pivot table based on
what it's fed. I'd suggest instead making your existing data models look
like a pivot table. Once that is working, you should see all the patterns
you need to refactor it into something reusable like an acts_as_pivot_table.
For the sparse data, ignore it. Build a wrapper to make it look full if
you need.
-david
On Oct 18, 2006, at 1:30 PM, Bryan Donovan wrote:
Hi,
I'm working on a class that I'll use in some rails applications that are
used to display data in cross-tabulation format (or as it's called in Excel,
a "pivot table"). Right now I'm taking an ActiveRecord object, specifying
what fields should go where in the crosstab, and then generating a big
nested hash (which I call a "tree", but not sure if that's the right
terminology). This isn't too difficult if I always know how many levels the
tree will have, etc., but I want this to be flexible enough to handle any
reasonable number of levels. I've also generated crosstab datasets with SQL
directly, but it gets a bit hard to follow and in my current situation, the
query runs slowly. This is a bit difficult to explain, so I've put up a web
page with an example hash and the desired output here:
http://bryandonovan.com/pastes/crosstab.html
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