title: How do I subtract 1 from each number in an array?
body: <p>If I have </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
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  <pre class="snippet-code-js lang-js prettyprint-override"><code>var numberarr = [1, 2, 3, 4, 5];</code></pre>
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  <p>How would i make it into </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
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  <pre class="snippet-code-js lang-js prettyprint-override"><code>var numberarr2 = [0, 1, 2, 3, 4];</code></pre>
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  <p>by decrementing 1 from each element?</p>