CSV Files

The simplest form for storing spreadsheet data are comma separated values (CSV) in a text file. Each line of a CSV file contains one row of the spreadsheet. The columns are separated by commas and sometimes by another symbol. CSV files may contain column headers in their first line(s).

A typical CSV file looks like that:

first_name,last_name,town
John,Miller,Atown
Ann,Abor,Betown
Bob,Builder,Cetown
Nina,Morning,Detown

CSV files are not standardized. Thus, there might be cumbersome deviations from what one expects to be a simple CSV file. The CSV format is used to move data between different sources which cannot read each others native file formats.

In Python we can use the module csv for reading data from CSV files. It provides the class csv.reader. When creating a csv.reader object we have to pass a file object of the CSV file as parameter. The csv.reader object then is an iterator object. It yields one line of the CSV file per iteration. More precisely, it yields a list of strings. Each string contains the data from the corresponding column.

See documentation of csv module for details.