sum rows based on unique columns awk - awk

Question

I'm looking for a more elegant way to do this (for more than >100 columns):
awk '{a[$1]+=$4}{b[$1]+=$5}{c[$1]+=$6}{d[$1]+=$7}{e[$1]+=$8}{f[$1]+=$9}{g[$1]+=$10}END{for(i in a) print i,a[i],b[i],c[i],d[i],e[i],f[i],g[i]}'
Here is the input:
a1 1 1 2 2
a2 2 5 3 7
a2 2 3 3 8
a3 1 4 6 1
a3 1 7 9 4
a3 1 2 4 2
and output:
a1 1 1 2 2
a2 4 8 6 15
a3 3 13 19 7
Thanks :)

Answer 1

I break the one-liner down into lines, to make it easier to read.
awk '{n[$1];for(i=2;i<=NF;i++)a[$1,i]+=$i}
END{for(x in n){
printf "%s ", x
for(y=2;y<=NF;y++)printf "%s%s", a[x,y],(y==NF?ORS:FS)
}
}' file
this awk command should work with your 100 columns file.
test with your file:
kent$ cat f
a1 1 1 2 2
a2 2 5 3 7
a2 2 3 3 8
a3 1 4 6 1
a3 1 7 9 4
a3 1 2 4 2
kent$ awk '{n[$1];for(i=2;i<=NF;i++)a[$1,i]+=$i}END{for(x in n){printf "%s ", x;for(y=2;y<=NF;y++)printf "%s%s", a[x,y],(y==NF?ORS:OFS)}}' f
a1 1 1 2 2
a2 4 8 6 15
a3 3 13 19 7

Answer 2

Using arrays of arrays in gnu awk version 4
awk '{for (i=2;i<=NF;i++) a[$1][i]+=$i}
END{for (i in a)
{ printf i FS;
for (j in a[i]) printf a[i][j] FS
printf RS}
}' file
a1 1 1 2 2
a2 4 8 6 15
a3 3 13 19 7

Answer 3

If you care about order of output try this
$ cat file
a1 1 1 2 2
a2 2 5 3 7
a2 2 3 3 8
a3 1 4 6 1
a3 1 7 9 4
a3 1 2 4 2
Awk Code :
$ cat tester
awk 'FNR==NR{
U[$1] # Array U with index being field1
for(i=2;i<=NF;i++) # loop through columns thats is column2 to NF
A[$1,i]+=$i # Array A holds sum of columns
next # stop processing the current record and go on to the next record
}
($1 in U){ # Here we read same file once again,if field1 is found in array U, then following statements
for(i=1;i<=NF;i++)
s = s ? s OFS A[$1,i] : A[$1,i] # I am writing sum to variable s since I want to use only one print statement, here you can use printf also
print $1,s # print column1 and variable s
delete U[$1] # We have done, so delete array element
s = "" # reset variable s
}' OFS='\t' file{,} # output field separator is tab you can set comma also
Resulting
$ bash tester
a1 1 1 2 2
a2 4 8 6 15
a3 3 13 19 7
If you want to try this on a Solaris/SunOS system, change awk to /usr/xpg4/bin/awk , /usr/xpg6/bin/awk , or nawk
--edit--
As requested in comment here is one liner, in above post for better reading purpose I had commented and it became several lines.
$ awk 'FNR==NR{U[$1];for(i=2;i<=NF;i++)A[$1,i]+=$i;next}($1 in U){for(i=1;i<=NF;i++)s = s ? s OFS A[$1,i] : A[$1,i];print $1,s;delete U[$1];s = ""}' OFS='\t' file{,}
a1 1 1 2 2
a2 4 8 6 15
a3 3 13 19 7