title: NameError: global name 'find' is not defined
body: <p>I'm a newbie of python.
  Now I'm struggling with python.</p>
  
  <p>I want to limit the region (longitude and latitude) </p>
  
  <pre><code>i = find((D[:, 2] &gt;= -120.) 
            &amp; (D[:, 2] &lt;= -110.) 
            &amp; (D[:, 3] &gt;= -75.) 
            &amp; (D[:, 3] &lt;= -71.))
  </code></pre>
  
  <p>But Error occurred.</p>
  
  <pre><code>---&gt; 21     i = find((D[:, 2]&gt;=-120.) &amp; (D[:, 2]&lt;=-110.) &amp; (D[:, 3]&gt;=-75.) &amp; (D[:, 3]&lt;=-71.))
       22     MN = mean(D[i, :], axis=0)
       23     STD = std(D[i, :], axis=0, ddof=1)
  NameError: global name 'find' is not defined
  </code></pre>
  
  <p>Why this error occurred? How can I solve this problem? </p>
  
  <p>Thanks in advance.</p>