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  1. PO
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    <p>It looks to me like you really want a <a href="http://guava-libraries.googlecode.com/svn/trunk/javadoc/com/google/common/collect/Multimap.html" rel="nofollow noreferrer">MultiMap</a>. In particular, <a href="http://guava-libraries.googlecode.com/svn/trunk/javadoc/com/google/common/collect/ArrayListMultimap.html" rel="nofollow noreferrer">ArrayListMultimap</a> allows duplicate entries:</p> <pre><code>ArrayListMultimap&lt;String, String&gt; map = ArrayListMultimap.create(); for each line in file: parse key k for each value in line: parse value v map.put(k, v); for (Map.Entry&lt;String,String&gt; entry : map.entries()) { String key = entry.getKey(); String value = entry.getValue(); } </code></pre> <hr> <p>If you want a cartesian product of maps, you could compute that directly using recursion, or you could iterate over the maps: create a list of iterators and iterate odometer-style; when iterator N reaches its end, advance iterator N+1 and reset iterators 1..N.</p> <hr> <p>Just poked around and found this SO question: <a href="https://stackoverflow.com/questions/1719594/iterative-cartesian-product-in-java">Iterative Cartesian Product in Java</a></p> <p>So I'd recommend you use guava's <a href="http://guava-libraries.googlecode.com/svn/tags/release04/javadoc/com/google/common/collect/Sets.html#cartesianProduct%28java.util.Set...%29" rel="nofollow noreferrer">Sets.cartesianProduct</a> for the cartesian product. Here's my poking around code, which you could adapt to your input logic:</p> <pre><code> String key1 = "a"; Set&lt;Integer&gt; values1 = Sets.newLinkedHashSet(Arrays.asList(1, 2, 3, 4 )); String key2 = "b"; Set&lt;Integer&gt; values2 = Sets.newLinkedHashSet(Arrays.asList(5, 6, 7)); String key3 = "c"; Set&lt;Integer&gt; values3 = Sets.newLinkedHashSet(Arrays.asList(8, 9)); List&lt;String&gt; keys = Arrays.asList(key1, key2, key3); Set&lt;List&lt;Integer&gt;&gt; product = Sets.cartesianProduct(values1, values2, values3); for (List&lt;Integer&gt; values : product) { for (int i = 0; i &lt; keys.size(); ++i) { String key = keys.get(i); int value = values.get(i); System.out.print(key + "=" + value + "; "); } System.out.println(); } </code></pre>
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    1. POrecursive iterate hashmap
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    1. USCommunity
    1. USMichael Brewer-Davis
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    1. COi don't want duplicate entries. i just want every k,v-combination. i am not concerned what the values are.
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      1. USzyamat
    2. COA `HashMultimap` would prevent duplicate entries. But I'm still really unclear on your goal.
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      1. USMichael Brewer-Davis
    3. COok. i get a text-input. this gets into the map. key is a. the values are stored in a String[]. i need the values later as separate strings. so that is why it is String[] and not just string. i need every combination from the key-value-pairs as in my first post.
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