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

Suggestions


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



@(coll)@{name /[^,]+/}@(end)
@(collect :vars (value sum))
@  (bind sum 0)
@  (coll)@{value /[^,]+/}@(set sum @(+ sum (int-str value)))@(end)
@(end)
@(output)
@  (rep)@name,@(last)SUM@(end)
@  (repeat)
@    (rep)@value,@(last)@sum@(end)
@  (end)
@(end)
 