title: Minimum values excluding 0 (data frame rows)
body: <pre><code>datas[1:n_row, ]    
                         IBOV     ABEV3 AEDU3 ALLL3
  1       2000-01-03 1.0120990 0.0000000     0     0
  2       2000-01-04 0.9860183 0.1463091     0     0
  3       2000-01-05 0.9565528 0.1876168     0     0
  4       2000-01-06 0.9286969 0.2059637     0     0
  5       2000-01-07 0.9163109 0.1996892     0     0
  6       2000-01-10 0.8943083 0.2147309     0     0
  </code></pre>
  
  <p>I m using :</p>
  
  <pre><code>MIN = apply(EWMA_SD252[,2:102],1,min)
  </code></pre>
  
  <p>to create another matrix of row minimuns, but i want to get the MIN values excluding 0 (values are always positive)
  any ideias ?</p>