Bash group by on the basis of n number of columns - bash

Question

This is related to my previous question that I [asked] (bash command for group by count)
What if I want to generalize this? For instance
The input file is
ABC|1|2
ABC|3|4
BCD|7|2
ABC|5|6
BCD|3|5
The output should be
ABC|9|12
BCD|10|7
The result is calculated by group first column and adding the values of 2nd column, and 3rd column, just like similar to group by command in SQL.
I tried modifying the command provided in the link but failed. I don't know whether I'm making a conceptual error or a silly mistake but all I know is none of the mentioned commands aren't working.
Command used
awk -F "|" '{arr[$1]+=$2} END arr2[$1]+=$5 END {for (i in arr) {print i"|"arr[i]"|"arr2[i]}}' sample
awk -F "|" '{arr[$1]+=$2} END {arr2[$1]+=$5} END {for (i in arr) {print i"|"arr[i]"|"arr2[i]}}' sample
awk -F "|" '{arr[$1]+=$2 arr2[$1]+=$5} END {for (i in arr2) {print i"|"arr[i]"|"arr2[i]}}' sample
Additionally, what if I'm trying here is to limit the use to summing the columns upto 2 only. What if there are n columns and we want to perform operations such as addition in one column and subtraction in other? How can that further be modified?
Example
ABC|1|2|4|......... upto n columns
ABC|4|5|6|......... upto n columns
DEF|1|4|6|......... upto n columns
lets say if sum is needed with first column, average may be for second column, some other operation for third column, etc. How this can be tackled?

Answer 1

For 3 fields (key and 2 data fields):
$ awk '
BEGIN { FS=OFS="|" } # set separators
{
a[$1]+=$2 # sum second field to a hash
b[$1]+=$3 # ... b hash
}
END { # in the end
for(i in a) # loop all
print i,a[i],b[i] # and output
}' file
BCD|10|7
ABC|9|12
More generic solution for n columns using GNU awk:
$ awk '
BEGIN { FS=OFS="|" }
{
for(i=2;i<=NF;i++) # loop all data fields
a[$1][i]+=$i # sum them up to related cells
a[$1][1]=i # set field count to first cell
}
END {
for(i in a) {
for((j=2)&&b="";j<a[i][1];j++) # buffer output
b=b (b==""?"":OFS)a[i][j]
print i,b # output
}
}' file
BCD|10|7
ABC|9|12
Latter only tested for 2 fields (busy at a meeting :).

Answer 2

gawk approach using multidimensional array:
awk 'BEGIN{ FS=OFS="|" }{ a[$1]["f2"]+=$2; a[$1]["f3"]+=$3 }
END{ for(i in a) print i,a[i]["f2"],a[i]["f3"] }' file
a[$1]["f2"]+=$2 - summing up values of the 2nd field (f2 - field 2)
a[$1]["f3"]+=$3 - summing up values of the 3rd field (f3 - field 3)
The output:
ABC|9|12
BCD|10|7
Additional short datamash solution (will give the same output):
datamash -st\| -g1 sum 2 sum 3 <file
-s - sort the input lines
-t\| - field separator
sum 2 sum 3 - sums up values of the 2nd and 3rd fields respectively

Answer 3

awk -F\| '{ array[$1]="";for (i=1;i<=NF;i++) { arr[$1,i]+=$i } } END { for (i in array) { printf "%s",i;for (p=2;p<=NF;p++) { printf "|%s",arr[i,p] } print "\n" } }' filename
We use two arrays, (array and arr) array is a single dimensional array tracking all the first pieces and arr is a multidimensional array keyed on the first piece and then the piece index and so for example arr["ABC",1]=1 and arr["ABC",2]=2. At the end we loop through array and then each field in the data set, we pull out the data from the multidimensional array arr.

Answer 4

This will work in any awk and will retain the input keys order in the output:
$ cat tst.awk
BEGIN { FS=OFS="|" }
!seen[$1]++ { keys[++numKeys] = $1 }
{
for (i=2;i<=NF;i++) {
sum[$1,i] += $i
}
}
END {
for (keyNr=1; keyNr<=numKeys; keyNr++) {
key = keys[keyNr]
printf "%s%s", key, OFS
for (i=2;i<=NF;i++) {
printf "%s%s", sum[key,i], (i<NF?OFS:ORS)
}
}
}
$ awk -f tst.awk file
ABC|9|12
BCD|10|7