8.4.3. CSV Workbook

import csv
import logging
import pprint

from stingray.workbook.base import Workbook
import stingray.sheet
import stingray.cell

class workbook.csv.CSV_Workbook

Extract sheets, rows and cells from a CSV file.

A wrapper for csv.reader(). This will create proper cell.TextCell instances instead of the default string values that csv normally creates.

There’s only a single sheet and it matches the filename.

In addition to the superclass attributes, an additional unique attribute is introduced here.

rdr

The csv reader for this file.

class CSV_Workbook( Workbook ):
    """Uses ``csv.reader``.  There's one sheet only."""
    def __init__( self, name, file_object=None, **kw ):
        """Prepare the workbook for reading.
        :param name: File name
        :param file_object: Optional file-like object.  If omitted, the named file is opened.
            If provided, it must be opened with  newline='' to permit non-standard
            line-endings.

        The kw are passed to :py:func:`csv.reader`
        to provide dialect information."""
        super().__init__( name, file_object )
        if self.file_obj:
            self.the_file= None
            self.rdr= csv.reader( self.file_obj, **kw )
        else:
            self.the_file = open( name, 'r', newline='' )
            self.rdr= csv.reader( self.the_file, **kw )

We can build an eager sheet.Row or a sheet.LazyRow from the available data. The eager Row includes the conversions. The sheet.LazyRow defers the conversions until the callback to workbook.base.Workbook.row_get().

CSV_Workbook.rows_of(sheet)

Iterator through all rows. The sheet is ignored.

def rows_of( self, sheet ):
    """An iterator over all rows of the named sheet.
    For CSV files, the sheet.name is simply ignored.
    """
    for data in self.rdr:
        logging.debug( pprint.pformat( data, indent=4 ) )
        row = stingray.sheet.Row( sheet, *(stingray.cell.TextCell(col,self) for col in data) )
        yield row

CSV_Workbook.row_get(row, attribute)

Concrete implementation to get an attribute’s value from a given row.

def row_get( self, row, attribute ):
    """Create a Cell from the row's data."""
    return row[attribute.position]

Since csv is eager, returning an individual cell.TextCell is easy.