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POHow to create a tree-like array from a loop?
 

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  1. POHow to create a tree-like array from a loop?
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    <p>Suppose I have a one-dimensional array <code>$arr</code> like this:</p> <pre><code>Array ( ['key1'] =&gt; 1 ['key2'] =&gt; 1 ['key3'] =&gt; 1 ['key4'] =&gt; 1 ) </code></pre> <p>I want to loop through <code>$arr</code> like this:</p> <pre><code>foreach($arr as $key =&gt; $a) { //$tree[????] = ????? Here is my concern } </code></pre> <p>such that, doing <code>print_r($tree)</code> produces</p> <pre><code>Array ( ['key1'] =&gt; Array ( ['key2'] =&gt; Array ( ['key3'] =&gt; Array ( ['key4'] =&gt; 1 ) ) ) ) </code></pre> <p>My concern is how to increase the dimension (not the values) of the array <code>$tree</code> inside the loop from a single dimension array <code>$numbers</code> such that <code>$tree['key1']['key2']['key3']</code> is an array and <code>$tree['key1']['key2']['key3']['key4']</code> is equal to <code>1</code>.</p> <p>Furthermore, if I have a single dimensional array <code>$foo</code> with 10 elements. I should produce another array <code>$bar</code> that expands to 10 dimensional array similar to the output above.</p> <p>What should I do inside the <code>foreach</code> loop? Or instead of using loop, is there a way to produce an output like that of above from a one dimension array?</p> <hr> <p>EDIT:</p> <blockquote> <p>OK well you obviously need some kind of recursive function, but can you explain how you know that key2 should be a child of key1, key3 should be a child of key2 etc based on the data you show?</p> </blockquote> <p>The next element of a 1D array is a child of the previous element. So if the 1D array is like this:</p> <pre><code>Array ( ['bar'] =&gt; 1 // I don't care of the values as of the moment ['foo'] =&gt; 1 ['baz'] =&gt; 1 ) </code></pre> <p>Element <code>foo</code> should be the child of <code>bar</code>, and element <code>baz</code> should be the child of <code>foo</code> for the tree array.</p> <blockquote> <p>Ok so the actual values of everything except the last element are irrelevant?</p> </blockquote> <p>Actually all values of the 1D array is irrelevant as of this moment. I am only concerned on constructing the tree array.</p>
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    1. USNeigyl R. Noval
    1. USNeigyl R. Noval
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    1. COOK well you obviously need some kind of recursive function, but can you explain how you know that `key2` should be a child of `key1`, `key3` should be a child of `key2` etc based on the data you show?
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      1. POHow to create a tree-like array from a loop?
      1. USDaveRandom
    2. COHi @DaveRandom. Please see edits.
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    3. COOk so the actual values of everything except the last element are irrelevant?
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      1. USDaveRandom
 

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