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.



>>filein: read/lines %file.csv
>>data: copy []
>>foreach item filein [append/only data split item ","]
; [["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"]]