Issues with OFS and sort working together in Bash - awk

Question

Given this type of input:
1,Name1,Type1,100,50
2,Name2,Type2,85,80
3,Name3,Type3,95,92
4,Name4,Type4,60,55
5,Name5,Type5,87,77
I want to calculate the average of the last 2 values and then sort them in decreasing order, so I wrote this bash code:
awk 'BEGIN{FS=","} {avg=($4+$5)/2;print $1,$3,avg}' | sort -k3 -nr
which gives me this output which is very close to my expected output:
3 Type3 93.5
2 Type2 82.5
5 Type5 82
1 Type1 75
4 Type4 57.5
The final thing I want is to separate the output with | (pipes), so I use the variable OFS like this:
awk 'BEGIN{FS=",";OFS="|"} {avg=($4+$5)/2;print $1,$3,avg}' | sort -k3 -nr
The output from this:
5|Type5|82
4|Type4|57.5
3|Type3|93.5
2|Type2|82.5
1|Type1|75
It seems like OFS is breaking the sort. Is this behaviour expected? Is there any workaround for this?

Answer 1

There are 2 issues in your shown code attempt. First is Input_file name is not passed in awk code(could be typo), 2nd is you need to set delimiter in sort by using -t'|' option so it will be like:
awk 'BEGIN{FS=",";OFS="|"} {avg=($4+$5)/2;print $1,$3,avg}' Input_file | sort -t'|' -k3 -nr
3|Type3|93.5
2|Type2|82.5
5|Type5|82
1|Type1|75
4|Type4|57.5
OR in a non-one liner form of code + removing avg variable you could get average of columns during printing of itself(in case you are using avg variable further any where in program then you could create it):
awk '
BEGIN{
FS=","
OFS="|"
}
{
print $1,$3,($4 + $5)/2
}' Input_file |
sort -t'|' -k3 -nr
From man sort page:
-t, --field-separator=SEP
use SEP instead of non-blank to blank transition

Answer 2

Some more way,actually you can also use awk's print with sort :
$ cat testfile.csv
1,Name1,Type1,100,50
2,Name2,Type2,85,80
3,Name3,Type3,95,92
4,Name4,Type4,60,55
5,Name5,Type5,87,77
$ awk 'BEGIN{FS=",";OFS="|"}{print $1,$3,($4+$5)/2 | "sort -t \"|\" -nrk3"}' testfile.csv
3|Type3|93.5
2|Type2|82.5
5|Type5|82
1|Type1|75
4|Type4|57.5

Answer 3

Using GNU awk's controlling array traversal feature:
gawk '
BEGIN { FS = ","; SUBSEP = "|" }
{ avg = ($4+$5)/2; result[$1,$3,avg] = avg }
END {
PROCINFO["sorted_in"] = "#val_num_desc"
for (line in result) print line
}
' testfile.csv
3|Type3|93.5
2|Type2|82.5
5|Type5|82
1|Type1|75
4|Type4|57.5
SUBSEP is the variable that holds the join string for comma-separated array keys. It's default value is octal 034, the "FS" character.