title: Group by its count from datatable in C#
body: <p>I am new to linq.</p>
  <p>I have a datatable and need to update a column according to another column using linq.</p>
  <p>My value</p>
  <pre><code>customer | value1  |  value2  | count
  ---------------------------------------- 
     A     |   sda   |  sdas    |  0
     A     |   sda   |  sdas    |  0
     B     |   sda   |  sdas    |  0
     B     |   sda   |  sdas    |  0
     B     |   sda   |  sdas    |  0
     C     |   sda   |  sdas    |  0
  </code></pre>
  <p>Expected Value</p>
  <pre><code>customer | value1  |  value2  | count
  ---------------------------------------- 
     A     |   sda   |  sdas    |  2
     A     |   sda   |  sdas    |  2
     B     |   sda   |  sdas    |  3
     B     |   sda   |  sdas    |  3
     B     |   sda   |  sdas    |  3
     C     |   sda   |  sdas    |  1
  </code></pre>
  <p>Could you please suggest me the required linq for the above datatable?</p>