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.



void main() {
    import std.stdio, std.csv, std.file, std.typecons, std.array,
           std.algorithm, std.conv, std.range;
 
    auto rows = "csv_data_in.csv".File.byLine;
    auto fout = "csv_data_out.csv".File("w");
    fout.writeln(rows.front);
    fout.writef("%(%(%d,%)\n%)", rows.dropOne
                .map!(r => r.csvReader!int.front.map!(x => x + 1)));
}