import xlrd 
def open_excel(fileName="simple.xls"):
  try:
    fileHandler = xlrd.open_workbook(fileName)
    return fileHandler
  except Exception, e:
    print str(e)  
def scan_excel(sheet_name1=u'Sheet1'):
  handler = open_excel()
  page = handler.sheet_by_name(sheet_name1)
  return page
def trim_cols(index=0):
  page = scan_excel()
  col1 = page.col_values(index)
  col2 = []
  for item in col1:
    if item not in col2:
      col2.append(item)
  print col1
  print col2
def main():
  trim_cols()
if __name__ == "__main__":
  main()  

[1.0, 2.0, 3.0, 4.0, 1.0, 2.0, 3.0, 4.0]
[1.0, 2.0, 3.0, 4.0]