Awk/Perl/Sed column substitution based on a text code - perl

Question

I have a text file with the following content
L,4m,06/03/2013
L,33GJm,06/03/2013,G
L,44Bm,06/03/2013,B
L,4q,08/03/2013
J,4m,04/03/2013
J,3GU,04/03/2013,G
J,3jm,04/03/2013
J,3GJ,04/03/2013,G
J,44Bm,06/03/2013,B
J,34Bq,08/03/2013,B
M,4v,12/03/2013
D,3GU,12/03/2013,G
D,4B,11/03/2013,B
D,4m,12/03/2013
D,3GJ,13/03/2013,G
D,3GU,13/03/2013,G
D,4B,14/03/2013,B
D,4B,14/03/2013,B
D,34Bm,14/03/2013,B
L,33BUq,11/03/2013,B
L,3BJUq,11/03/2013,B
L,44Bq,14/03/2013,B
L,44Bq,14/03/2013,B
L,3Bq,15/03/2013,B
L,3q,15/03/2013
J,34Bjq,11/03/2013,B
J,33GUm,12/03/2013,G
J,4q,13/03/2013
J,33GUq,13/03/2013,G
J,33GUq,13/03/2013,G
J,4q,13/03/2013
M,3BU,18/03/2013,B
M,4B,18/03/2013,B
M,4B,18/03/2013,B
M,3GJ,19/03/2013,G
M,3GJ,19/03/2013,G
D,4B,22/03/2013,B
D,3BU,22/03/2013,B
L,34Bv,18/03/2013,B
L,3jm,19/03/2013
L,4m,19/03/2013
L,33GJm,19/03/2013,G
L,33GUm,19/03/2013,G
J,33BUm,18/03/2013,B
J,4m,18/03/2013
J,4B,18/03/2013,B
J,33BUm,18/03/2013,B
J,4q,22/03/2013
J,4q,22/03/2013
A,3GJ,28/03/2013,G
M,4B,27/03/2013,B
D,4B,25/03/2013,B
L,44Bq,25/03/2013,B
L,34Bq,25/03/2013,B
L,34Bq,25/03/2013,B
L,33BUa,26/03/2013,B
L,33BUq,26/03/2013,B
L,33BUq,26/03/2013,B
L,34Bq,27/03/2013,B
L,34Bq,27/03/2013,B
L,4B,27/03/2013,B
L,34Bq,27/03/2013,B
L,4a,28/03/2013
I want to translate the second column based on the following coding system.
If $2 starts with a 1 or 2 - Change $2 to Excellent
If $2 contains 3BU or 3GU - Change $2 to Good
if $2 contains 3BJ or 3GJ - Change $2 to OK
If $2 starts with a 4 - Change $2 to Poor
If $2 starts with a 5 - Change $2 Terrible
I can find and change the 3BUs to Good easy enough using the following command
awk 'BEGIN{FS=",";OFS=","} {if ($2~ /3(B|G)U/)print $1,"Good",$3}' file | sponge file
Though I use all other non 3(B|G)U lines. I could use if else terminology though this seems inelegant. I have tried to use gensub to solve the problem
awk -F, '{gensub(/3(B|G)U/,Good,"",2)}1' file
But this prints the file contents without substitution. Any hints
Desired output
L,Poor,06/03/2013
L,Ok,06/03/2013,G
L,Poor,06/03/2013,B
L,Poor,08/03/2013
J,Poor,04/03/2013
J,Good,04/03/2013,G
A perl or sed one-liner would also be helpful as this code forms part of a bash shell script

Answer 1

If you want to stick with shell:
(
IFS=,
while read -ra f; do # pick more appropriate variable names
case ${f[1]} in
[12]*) f[1]=Excellent ;;
*3[BG]U*) f[1]=Good ;;
*3[BG]J*) f[1]=OK ;;
4*) f[1]=Poor ;;
5*) f[1]=Terrible ;;
esac
echo "${f[*]}"
done < file
) > tmp && mv tmp file
I ran that in a subshell to localize changes to $IFS

Answer 2

a sed solutions too
sed -e 's/\(^.,\)\(1\|2\)[^,]*/\1Excellent/g' -e 's/\(^.,\)3[BG]U[^,]*/\1Good/g' -e 's/\(^.,\)3[BG]J[^,]*/\1OK/g' -e 's/\(^.,\)4[^,]*/\1Poor/g' -e 's/\(^.,\)5[^,]*/\1Terrible/g' <filename>

Answer 3

$ awk '
BEGIN { FS=OFS="," }
$2 ~ /^(1|2)/ { $2 = "Excellent" }
$2 ~ /3(B|G)U/ { $2 = "Good" }
$2 ~ /3(B|G)J/ { $2 = "OK" }
$2 ~ /^4/ { $2 = "Poor" }
$2 ~ /^5/ { $2 = "Terrible" }
1
' foo.txt | head -n 10
L,Poor,06/03/2013
L,OK,06/03/2013,G
L,Poor,06/03/2013,B
L,Poor,08/03/2013
J,Poor,04/03/2013
J,Good,04/03/2013,G
J,3jm,04/03/2013
J,OK,04/03/2013,G
J,Poor,06/03/2013,B
J,34Bq,08/03/2013,B

Answer 4

perl -pe 's{,(\w+)}{ $_ = /^[12]/ ?"Excellent" :/3[BG]U/ ?"Good" :/3[BG]J/ ?"OK" :/^4/ ?"Poor" :/^5/ ?"Terrible" :$_ for $v=$1; ",$v" }e'
More readable version,
s{,(\w+)}{
for ($v = $1) {
$_ = /^[12]/ ?"Excellent"
:/3[BG]U/ ?"Good"
:/3[BG]J/ ?"OK"
:/^4/ ?"Poor"
:/^5/ ?"Terrible"
:$_;
}
",$v";
}e;