title: If I leave the 'for' statement, the data will disappear
body: <p>I did for loop. but The data in for loop is valid. but the data disappear except a few. I don't know why it is. I used two for loop(not same each other). and The two is same. I work in jupyter note. but I don't know this is the reason. </p>
  
  <p>In the first for loop. I thought It just my mistake. so I save the file as CSV in the first for loop. but In the second for loop, the problem appear.</p>
  
  <pre><code>for i in range(0,191):
  
      coord_i = np.load(''+st[i].id+'.npy')
      print(coord_i)   # It is valid. I can see all coord_i. because It is in this for loop
  
  print(coord_1)   # error : name 'coord_1' is not defined. beacuse It is not in above for loop
  </code></pre>
  
  <p>I don't know what I miss. Please help me.</p>