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POHow do I keep the hash associations when building permutations
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  1. POHow do I keep the hash associations when building permutations
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    copied!<p>UPDATE: Possible solution at the end, but certainly not performant or ideal.</p> <p>I created the following method that gives me close to what I want.</p> <pre><code>def multi_permutations(collection) case collection.length when 1 return collection.shift[1] when 0 raise "You must pass in a multidimensional collection." end a = collection.shift[1] b = multi_permutations(collection) return_value = [] a.each do |a_value| b.each do |b_value| return_value &lt;&lt; [a_value] + [b_value] end end return return_value end </code></pre> <p>When I pass in a hash with nested arrays that looks like this...</p> <pre><code>my_collection["item_9"] = [152] my_collection["item_2"] = [139, 143, 145] my_collection["item_13"] = [138, 142, 150] my_collection["item_72"] = [137, 149, 151, 154] my_collection["item_125"] = [140, 141] my_collection["item_10"] = [144, 146, 147, 148, 153] </code></pre> <p>I want it to create an array of hashes with all permutations that looks like this...</p> <pre><code>[{ "item_9": 152 }, { "item_2": 139 }, { "item_13": 138 }, { "item_72": 137 }, { "item_125": 140 }, { "item_10": 144 }] [{ "item_9": 152 }, { "item_2": 139 }, { "item_13": 138 }, { "item_72": 137 }, { "item_125": 140 }, { "item_10": 146 }] [{ "item_9": 152 }, { "item_2": 139 }, { "item_13": 138 }, { "item_72": 137 }, { "item_125": 140 }, { "item_10": 147 }] [{ "item_9": 152 }, { "item_2": 139 }, { "item_13": 138 }, { "item_72": 137 }, { "item_125": 140 }, { "item_10": 148 }] [{ "item_9": 152 }, { "item_2": 139 }, { "item_13": 138 }, { "item_72": 137 }, { "item_125": 140 }, { "item_10": 153 }] . . . [{ "item_9": 152 }, { "item_2": 145 }, { "item_13": 150 }, { "item_72": 154 }, { "item_125": 141 }, { "item_10": 144 }] [{ "item_9": 152 }, { "item_2": 145 }, { "item_13": 150 }, { "item_72": 154 }, { "item_125": 141 }, { "item_10": 146 }] [{ "item_9": 152 }, { "item_2": 145 }, { "item_13": 150 }, { "item_72": 154 }, { "item_125": 141 }, { "item_10": 147 }] [{ "item_9": 152 }, { "item_2": 145 }, { "item_13": 150 }, { "item_72": 154 }, { "item_125": 141 }, { "item_10": 148 }] [{ "item_9": 152 }, { "item_2": 145 }, { "item_13": 150 }, { "item_72": 154 }, { "item_125": 141 }, { "item_10": 153 }] </code></pre> <p>What this function ends up doing is close but I lose the relationships.</p> <pre><code>[152, [139, [138, [137, [140, 144]]]]] [152, [139, [138, [137, [140, 146]]]]] [152, [139, [138, [137, [140, 147]]]]] [152, [139, [138, [137, [140, 148]]]]] [152, [139, [138, [137, [140, 153]]]]] . . . [152, [145, [150, [154, [141, 144]]]]] [152, [145, [150, [154, [141, 146]]]]] [152, [145, [150, [154, [141, 147]]]]] [152, [145, [150, [154, [141, 148]]]]] [152, [145, [150, [154, [141, 153]]]]] </code></pre> <p>The relationships are very important to me. The reason is, I plan to hydrate an object where the attrs are the keys in the hash. I'm sure this can be done in a better way, and I'm open to suggestions.</p> <p>So one possible solution I've come up with is to create a keys array then flatten the permutations and zip them together in a hash.</p> <pre><code> results = [] permutations = multi_permutations(possibilities) permutations.each do |permutation| results &lt;&lt; Hash[keys.zip permutation.flatten!] end </code></pre> <p>This ends up giving me...</p> <pre><code>{"item_9"=&gt;152, "item_2"=&gt;145, "item_13"=&gt;150, "item_72"=&gt;154, "item_125"=&gt;141, "item_10"=&gt;146} {"item_9"=&gt;152, "item_2"=&gt;145, "item_13"=&gt;150, "item_72"=&gt;154, "item_125"=&gt;141, "item_10"=&gt;147} {"item_9"=&gt;152, "item_2"=&gt;145, "item_13"=&gt;150, "item_72"=&gt;154, "item_125"=&gt;141, "item_10"=&gt;148} {"item_9"=&gt;152, "item_2"=&gt;145, "item_13"=&gt;150, "item_72"=&gt;154, "item_125"=&gt;141, "item_10"=&gt;153} </code></pre>
 

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