sum1.awk


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#!/usr/bin/awk -f

### sum1.awk, print column sums
# input: rows of numbers
# output: sum of each column
#   missing entries are treated as zeros


function isnum(n) {
    sign = "[+-]?"
    decimal = "[0-9]+[.]?[0-9]*"
    fraction = "[.][0-9]+"
    exponent = "([Ee]" sign "[0-9]+)?"
    number = "^" sign "(" decimal "|" fraction ")" exponent "$"
    return n ~ number
}


BEGIN {
    OFS = FS
}


NR == 1 {
    for (i=1; i<=NF; i++)
        isnum($i) ? header[i] = "col" i : header[i] = $i
}


NF > 0 {
    (NF > nf_max) ? nf_max = NF : nf_max = nf_max
    for (i=1; i<=NF; i++)
        sum[i] += $i
}


END {
    for (i=1; i<=nf_max; i++) {
        printf(OFMT, sum[i])
        printf((i < nf_max) ? OFS : ORS)
    }
}