awk : awk script to group by column with condition - awk

Question

I have tab delimited file like following and I am trying to write a awk script
aaa_log-000592 2 p STARTED 7027691 21.7 a1
aaa_log-000592 28 r STARTED 7027815 21.7 a2
aaa_log-000592 33 p STARTED 7032607 21.7 a3
aaa_log-000592 33 r STARTED 7032607 21.7 a4
aaa_log-000592 43 p STARTED 7025709 21.7 a5
aaa_log-000592 43 r STARTED 7025709 21.7 a6
aaa_log-000595 2 r STARTED 7027691 21.7 a7
aaa_log-000598 28 p STARTED 7027815 21.7 a8
aaa_log-000599 13 p STARTED 7033090 21.7 a9
I am trying to count for 3rd column (p or r) and group by column 1
Output would be like
Col1 Count-P Count-R
aaa_log-000592 3 3
aaa_log-000595 0 1
aaa_log-000598 1 0
aaa_log-000599 1 0
I can't find an example that would have IF condition with group by in awk.

Answer 1

awk(more specifically, the GNU variant, gawk) has multi-dimensional arrays that can be indexed using input values (including character strings like in your example). As such, you can count the values in the way you want by doing
{
values[$3] = 1 # this line records the values in column three
counts[$1][$3]++ # and this lines counts their frequency
}
The first line isn't strictly required, but it simplifies generating the output.
The only remaining part is to have an END clause that outputs the tabulated results.
END {
# Print column headings
printf "Col1 "
for (v in values) {
printf " Count-%s", v
}
printf "\n"
# Print tabulated results
for (i in counts) {
printf "%-20s", i
for (v in values) {
printf " %d", counts[i][v]
}
printf "\n"
}
}
Generating the values array handles the case when the values of column three may not be known (e.g., like when there's an error in your input).
If you're using a different awk implementation (like what you might find in macOS, for example), array indexing may be different (e.g., they are single-dimensional arrays, but indexed by a comma-separate list of indices). This may add some additional complexity, but the idea is the same.
{
files[$1] = 1
values[$3] = 1
counts[$1,$3]++
}
END {
# Print column headings
printf "Col1 "
for (v in values) {
printf " Count-%s", v
}
printf "\n"
# Print tabulated results
for (f in files) {
printf "%-20s", f
for (v in values) {
printf " %d", counts[f,v]
}
printf "\n"
}
}