code: def write_frame(
      df,
      directory,
      filename,
      extension,
      separator,
      index=False,
      index_label=None,
      columns=None,
  ):
      r"""Write a dataframe into a delimiter-separated file.
  
      Parameters
      ----------
      df : pandas.DataFrame
          The pandas dataframe to save to a file.
      directory : str
          Full directory specification.
      filename : str
          Name of the file to write, excluding the ``extension``.
      extension : str
          File name extension, e.g., ``csv``.
      separator : str
          The delimiter between fields in the file.
      index : bool, optional
          If ``True``, write the row names (index).
      index_label : str, optional
          A column label for the ``index``.
      columns : str, optional
          A list of column names.
  
      Returns
      -------
      None : None
  
      """
      file_only = PSEP.join([filename, extension])
      file_all = SSEP.join([directory, file_only])
      logger.info("Writing data frame to %s", file_all)
      try:
          df.to_csv(
              file_all,
              sep=separator,
              index=index,
              index_label=index_label,
              columns=columns,
          )
      except:
          logger.info("Could not write data frame to %s", file_all)
  
file_path: AlphaPy/alphapy/frame.py
imports: from alphapy.globals import PSEP, SSEP, USEP
  from alphapy.globals import TAG_ID
  import logging
  import pandas
label_desc: Use image node_id 3 for calling a global function with example usage: write_frame(df, directory, filename, extension, separator, index, index_label, columns) without return types