title: General method of changing the value in a vector
body: <p>If I have</p>
  
  <pre><code>(def x [[1 2 3] [4 5 6]])
  </code></pre>
  
  <p>Is there a general method of changing any of the numbers to say 9</p>
  
  <p>I know I can do </p>
  
  <pre><code>(assoc-in x [1 1] 9) &gt; [[1 2 3] [4 9 6]]
  </code></pre>
  
  <p>Is there a way to do it if you don't know the index numbers. Or someway to find the index numbers first and all the information you have is you want to change the number 5 to number 9 in x</p>