How do I sum values of a column cumulatively with awk?

Question

I have a sample.csv and want to sum it cumulatively by column, as below:

Input csv:                        Output csv:
01/01/2020, 0, 0, 2, 1            01/01/2020, 0, 0, 2, 1
18/04/2022, 7, 5, 1, 3            18/04/2022, 7, 5, 3, 4
01/05/2022, 8,21, 9, 4            01/05/2022,15,26,12, 8

I've tried

awk '{ for (i=1; i<=NF; ++i) {sum[i]+=$i; $i=sum[i] }; print $0}' sample.csv

But it returns this instead:

Input csv:                        Output csv:
01/01/2020, 0, 0, 2, 1            01/01/2020, 0, 0, 2, 1, 0, 0, 0, 0, 0
18/04/2022, 7, 5, 1, 3            18/04/2022, 7, 5, 1, 3, 0, 0, 0, 0, 0
01/05/2022, 8,21, 9, 4            01/05/2022, 8,21, 9, 4, 0, 0, 0, 0, 0

I'm at a loss as to how to resolve this.

Note: I am writing this in a bash script, not the terminal. And I'm not allowed to use any tools other than awk for this

Answer 1

Tested and confirmed working on

• gawk 5.1.1,
• mawk 1.3.4,
• mawk 1.9.9.6, and
• macos nawk

——————————————————————————————————————————————

    # gawk profile, created Thu May 19 15:59:38 2022
    
    function fmt(_) {
        return +_<=_^(_<_) \
        ? "" : $_ = sprintf("%5.f",___[_]+=$_)
    }
    BEGIN { split(sprintf("%0*.f",((__=++_)+(++_*_)\
                                  )^++_,!_),___,"""")
            OFS = ", "
             FS = "[,][ ]*"
    } {       _ = NF                                    
        while(_!=__) { fmt(_--) } }_'

——————————————————————————————————————————————

01/01/2020,     0,     0,     2,     1
18/04/2022,     7,     5,     3,     4
01/05/2022,    15,    26,    12,     8