title: Loops in python does not loop through every line in file
body: <p>I am trying to loop through every line in a text file and perform some actions. Right now I have a text file which contains this:</p>
  
  <pre><code>--- small modified --- #line 1
  1,2,3                  #line 2
  4,5,6                  #line 3
  --- big modified ---   #line 4
  7;8;9                  #line 5
  10;11;12               #line 6
  </code></pre>
  
  <p>I am trying to parse line 2,3 into one file, and lines 5,6 into another file but right now, only lines 2 and 3 gets written into the file and idk why the "elif" statement is not run. I can't solve the logic error and would appreciate if someone could help me out.</p>
  
  <p>Below is my code:</p>
  
  <pre><code>def convert_json(fileName):
      with open(fileName,'r') as file:
          for line in file:
              if 'modified' and 'small' in line:
                  for li in file:
                      fields1 = li.split(',')
                      if len(fields1) &gt;= 3:
                              smallarr.append({
                              "a": fields1[0],
                              "b": fields1[1],
                              "c": fields1[2]
                                  })
                              with open('smalljson.txt','w+') as small_file:
                                  json.dump(smallarr, small_file)
                      else:
                          pass
  
              elif 'modified' and 'big' in line:
                  for li in file:
                      fields2 = li.split(';')
                      if len(fields2) &gt;= 3:
                              bigarr.append({
                              "w1": fields2[0],
                              "w2": fields2[1],
                              "w3": fields2[2],
                                  })
                              with open('big.txt','w+') as big_file:
                                  json.dump(bigarr, big_file)
                      else: 
                          pass
  
  
  
              else:
                  print 'test'
  </code></pre>
  
  <p>Update: THis is my current code, I am able to do it but only for lines 2 and lines 5, other than s second for-loop i cannot think of another way to loop through the lines</p>
  
  <pre><code>def convert_json(fileName):
  with open(fileName,'r') as file:
      for line in file:
          #if 'modified' in line and 'small' in line:
          if 'modified' in line and 'Small' in line:
              fields1 = next(file).split(',')
              if len(fields1) &gt;= 3:
                  smallarr.append({
                  "a": fields1[0],
                  "b": fields1[1],
                  "c": fields1[2]
                  })
                  with open('smalljson.txt','w+') as small_file:
                      json.dump(smallarr, small_file)
              else:
                  pass
  
  
  
          elif 'modified' in line and 'big' in line:
              fields2 = next(file).split(';')
              if len(fields2) &gt;= 3:
                  bigarr.append({
                  "w1": fields2[0],
                  "w2": fields2[1],
                  "w3": fields2[2],
                  })
                  with open('bigwater.txt','w+') as big_file:
                      json.dump(bigarr, big_file)
              else:
                  pass
  
          else:
              print 'test'
  </code></pre>