docs: def _readFile(self, sldir, fileName, sep):
          '''
          Private method that reads in the header and column data.
  
          '''
  
          if sldir.endswith(os.sep):
              fileName = str(sldir)+str(fileName)
          else:
              fileName = str(sldir)+os.sep+str(fileName)
  
  
          fileLines=[] #list of lines in the file
          header=[]    #list of Header lines
          dataCols=[]  #Dictionary of data column names
          data=[]      #List of Data lists
          cols=[]      #List of column names
  
          f=open(fileName,'r')
          fileLines=f.readlines()
          i=0
          if self.datatype != 'trajectory':
  
              while i<len(fileLines):
                  if fileLines[i].startswith(self.header_char):
                      tmp=fileLines[i].lstrip(self.header_char)
                      header.append(tmp.strip())
                  else:
                      break
                  i+=1
  
              cols=fileLines[i].split(sep)
  
              tmp=[]
              tmp1=[]
              for j in range(len(cols)):
                  tmp1=cols[j].strip()
                  if tmp1 !='':
                      tmp.append(tmp1)
              cols=tmp
              i+=1
          else:
              header={}
              while fileLines[i].startswith('#') or '=' in fileLines[i]:
                  if fileLines[i].startswith('#') and cols==[]:
                      cols=fileLines[i].strip('#')
                      cols=cols.strip()
                      cols=cols.split()
                  elif fileLines[i].startswith('#'):
                      tmp1=fileLines[i].strip('#')
                      tmp1=tmp1.strip()
                      self.headerLines.append(tmp1)
                  elif not fileLines[i].startswith('#'):
                      tmp=fileLines[i].split('=')
                      tmp[0]=tmp[0].strip()
                      tmp[1]=tmp[1].strip()
                      if header=={}:
                          header={str(tmp[0]):str(tmp[1])}
                      else:
                          header[str(tmp[0])]=str(tmp[1])
                  i+=1
          while i<len(fileLines):
              if fileLines[i].startswith('#'):
                  i=i+1
              else:
                  tmp=fileLines[i].split()
                  for j in range(len(tmp)):
                      tmp[j]=tmp[j].strip()
                  data.append(tmp)
                  i+=1
          tmp=[]
          tmp1=[]
          for j in range(len(data)):
              for k in range(len(data[j])):
                  tmp1=data[j][k].strip()
                  if tmp1 !='':
                      tmp.append(tmp1)
              data[j]=tmp
              tmp=[]
          tmp=[]
  
          for j in range(len(cols)):
              for k in range(len(data)):
                  try:
                      a=float(data[k][j])
                      tmp.append(a)
                  except ValueError:
                      tmp.append(data[k][j])
                  #else:
                   #   tmp.append(float(data[k][j])) # previously tmp.append(float(data[k][j]))
              tmp=array(tmp)
  
              if j == 0:
                  dataCols={cols[j]:tmp}
              else:
                  dataCols[cols[j]]=tmp
              tmp=[]
  
          return header,dataCols