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    <p>If you just want those probabilities in the long run, you can just get values by randomly selecting one element from the array {1,2,2,3,3,3,4,4,4,4}.</p> <p>If you however need to retrieve exactly 1000 elements, in those specific quantities, you can try something like this (not C#, but shouldn't be a problem):</p> <pre class="lang-java prettyprint-override"><code>import java.util.Random; import java.util.*; class Thing{ Random r = new Random(); ArrayList&lt;Integer&gt; numbers=new ArrayList&lt;Integer&gt;(); ArrayList&lt;Integer&gt; counts=new ArrayList&lt;Integer&gt;(); int totalCount; public void set(int i, int count){ numbers.add(i); counts.add(count); totalCount+=count; } public int getValue(){ if (totalCount==0) throw new IllegalStateException(); double pos = r.nextDouble(); double z = 0; int index = 0; //we select elements using their remaining counts for probabilities for (; index&lt;counts.size(); index++){ z += counts.get(index) / ((double)totalCount); if (pos&lt;z) break; } int result = numbers.get(index); counts.set( index , counts.get(index)-1); if (counts.get(index)==0){ counts.remove(index); numbers.remove(index); } totalCount--; return result; } } class Test{ public static void main(String []args){ Thing t = new Thing(){{ set(1,100); set(2,200); set(3,300); set(4,400); }}; int[]hist=new int[4]; for (int i=0;i&lt;1000;i++){ int value = t.getValue(); System.out.print(value); hist[value-1]++; } System.out.println(); double sum=0; for (int i=0;i&lt;4;i++) sum+=hist[i]; for (int i=0;i&lt;4;i++) System.out.printf("%d: %d values, %f%%\n",i+1,hist[i], (100*hist[i]/sum)); } } </code></pre>
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    1. POWhat algorithm can I use to produce 'Random' value?
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