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.



File_Open("input.csv")
for (#1 = 0; #1 < 4; #1++) {
    Goto_Line(#1+2)                             // line (starting from line 2)
    if (#1) {
        Search(",", ADVANCE+COUNT, #1)          // column
    }
    #2 = Num_Eval()                             // #2 = old value
    Del_Char(Chars_Matched)                     // delete old value
    Num_Ins(#2+100, LEFT+NOCR)                  // write new value
}
File_Save_As("output.csv", OK+NOMSG) 