text: # import pandas and load nls data
  import pandas as pd
  pd.set_option('display.width', 78)
  pd.set_option('display.max_columns', 7)
  pd.set_option('display.max_rows', 200)
  pd.options.display.float_format = '{:,.2f}'.format
  nls97 = pd.read_pickle("data/nls97b.pkl")
  
  # create a series from the GPA column
  gpaoverall = nls97.gpaoverall
  type(gpaoverall)
  gpaoverall.head()
  gpaoverall.index
  
  # select gpa values using bracket notation
  gpaoverall[:5]
  gpaoverall.tail()
  gpaoverall[-5:]
  
  # select values using loc
  gpaoverall.loc[100061]
  gpaoverall.loc[[100061]]
  gpaoverall.loc[[100061,100139,100284]]
  gpaoverall.loc[100061:100833]
  
  # select values using iloc
  gpaoverall.iloc[[0]]
  type(gpaoverall.iloc[[0,1,2,3,4]])
  gpaoverall.iloc[:5]
  gpaoverall.iloc[-5:]
  
  