title: How to optimize vlookup for high search count ? (alternatives to VLOOKUP)
body: <p>I am looking for alternatives to vlookup, with improved performance within the context of interest.</p>
  
  <p>The context is the following:</p>
  
  <ul>
  <li>I have a data set of {key;data} which is big (~ 100'000 records)</li>
  <li>I want to perform a lot of VLOOKUP operations on the dataset (typical use is to reorder the whole dataset)</li>
  <li>My data set has no duplicate keys</li>
  <li>I am looking only for exact matches (last argument to <code>VLOOKUP</code> is <code>FALSE</code>)</li>
  </ul>
  
  <p>A schema to explain :</p>
  
  <p>Reference sheet : (<code>"sheet1"</code>)</p>
  
  <pre><code>        A           B
       1
       2  key1        data1
       3  key2        data2
       4  key3        data3
     ...  ...         ...
   99999  key99998    data99998
  100000  key99999    data99999
  100001  key100000   data100000
  100002
  </code></pre>
  
  <p>Lookup sheet:</p>
  
  <pre><code>        A           B
       1
       2  key51359    =VLOOKUP(A2;sheet1!$A$2:$B$100001;2;FALSE)
       3  key41232    =VLOOKUP(A3;sheet1!$A$2:$B$100001;2;FALSE)
       4  key10102    =VLOOKUP(A3;sheet1!$A$2:$B$100001;2;FALSE)
     ...  ...         ...
   99999  key4153     =VLOOKUP(A99999;sheet1!$A$2:$B$100001;2;FALSE)
  100000  key12818    =VLOOKUP(A100000;sheet1!$A$2:$B$100001;2;FALSE)
  100001  key35032    =VLOOKUP(A100001;sheet1!$A$2:$B$100001;2;FALSE)
  100002
  </code></pre>
  
  <p>On my Core i7 M 620 @2.67 GHz, this computes in ~10 minutes</p>
  
  <p>Are there alternatives to VLOOKUP with better performance in this context ?</p>