[[wp:Comma-separated values|CSV spreadsheet files]] are suitable for storing tabular data in a relatively portable way.

The CSV format is flexible but somewhat ill-defined.

For present purposes, authors may assume that the data fields contain no commas, backslashes, or quotation marks.


;Task:
Read a CSV file, change some values and save the changes back to a file.

For this task we will use the following CSV file:

 C1,C2,C3,C4,C5
 1,5,9,13,17
 2,6,10,14,18
 3,7,11,15,19
 4,8,12,16,20

<i>Suggestions</i>
<ul>
<li/> Show how to add a column, headed 'SUM', of the sums of the rows.
<li/> If possible, illustrate the use of built-in or standard functions, methods, or libraries, that handle generic CSV files.
</ul>
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