class_docstr: Uses a Pandas DataFrame as the feed source, using indices into column
  names (which can be "numeric")
  
  This means that all parameters related to lines must have numeric
  values as indices into the tuples
  
  Params:
  
    - ``nocase`` (default *True*) case insensitive match of column names
  
  Note:
  
    - The ``dataname`` parameter is a Pandas DataFrame
  
    - Values possible for datetime
  
      - None: the index contains the datetime
      - -1: no index, autodetect column
      - >= 0 or string: specific colum identifier
  
    - For other lines parameters
  
      - None: column not present
      - -1: autodetect
      - >= 0 or string: specific colum identifier
class_docstr_tok: ["Uses","a","Pandas","DataFrame","as","the","feed","source",",","using","indices","into","column","names","(","which","can","be","``","numeric","''",")","This","means","that","all","parameters","related","to","lines","must","have","numeric","values","as","indices","into","the","tuples","Params",":","-","``","nocase","``","(","default","*","True","*",")","case","insensitive","match","of","column","names","Note",":","-","The","``","dataname","``","parameter","is","a","Pandas","DataFrame","-","Values","possible","for","datetime","-","None",":","the","index","contains","the","datetime","-","-1",":","no","index",",","autodetect","column","-",">","=","0","or","string",":","specific","colum","identifier","-","For","other","lines","parameters","-","None",":","column","not","present","-","-1",":","autodetect","-",">","=","0","or","string",":","specific","colum","identifier"]
code: def _load(self):
      self._idx += 1
  
      if self._idx >= len(self.p.dataname):
          # exhausted all rows
          return False
  
      # Set the standard datafields
      for datafield in self.getlinealiases():
          if datafield == "datetime":
              continue
  
          colindex = self._colmapping[datafield]
          if colindex is None:
              # datafield signaled as missing in the stream: skip it
              continue
  
          # get the line to be set
          line = getattr(self.lines, datafield)
  
          # indexing for pandas: 1st is colum, then row
          line[0] = self.p.dataname.iloc[self._idx, colindex]
  
      # datetime conversion
      coldtime = self._colmapping["datetime"]
  
      if coldtime is None:
          # standard index in the datetime
          tstamp = self.p.dataname.index[self._idx]
      else:
          # it's in a different column ... use standard column index
          tstamp = self.p.dataname.iloc[self._idx, coldtime]
  
      # convert to float via datetime and store it
      dt = tstamp.to_pydatetime()
      dtnum = date2num(dt)
      self.lines.datetime[0] = dtnum
  
      # Done ... return
      return True
  
file_path: backtrader/backtrader/feeds/pandafeed.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  from backtrader.utils.py3 import filter, string_types, integer_types
  from backtrader import date2num
  import backtrader.feed
label_desc: Use image node_id 3 for calling the PandasData obj's underlying member method code with example usage: obj._load() and returns: True, False