title: Introduction to Data Science in Python problem
body: <p>Can any one tell my what that part (town = thisLine[:thisLine.index('(')-1])exactly do?</p>
  
  <pre><code>def get_list_of_university_towns():
  '''Returns a DataFrame of towns and the states they are in from the 
  university_towns.txt list. The format of the DataFrame should be:
  DataFrame( [ ["Michigan", "Ann Arbor"], ["Michigan", "Yipsilanti"] ], 
  columns=["State", "RegionName"]  )
  
  The following cleaning needs to be done:
  1. For "State", removing characters from "[" to the end.
  2. For "RegionName", when applicable, removing every character from " (" to the end.
  3. Depending on how you read the data, you may need to remove newline character '\n'. '''
  
  data = []
  state = None
  state_towns = []
  with open('university_towns.txt') as file:
      for line in file:
          thisLine = line[:-1]
          if thisLine[-6:] == '[edit]':
              state = thisLine[:-6]
              continue
          if '(' in line:
              town = thisLine[:thisLine.index('(')-1]
              state_towns.append([state,town])
          else:
              town = thisLine
              state_towns.append([state,town])
          data.append(thisLine)
  df = pd.DataFrame(state_towns,columns = ['State','RegionName'])
  return df
  </code></pre>
  
  <p>get_list_of_university_towns()</p>