Shell Programming and Scripting

Not sure if my attempt below is close but I am trying to match $1 of gene.txt to $2 of medicalexome.txt,
and if there is a match then $2 $1 are copied to a new result.txt which is tab-delimited. If no match is found then
$1 of gene.txt and "No Match" are copied to the result file.

Code:

 awk 'FNR==NR { E[$1]=$2 ; next }
{ $1=$1 in E?E[$1]:"No Match" } 1' medicalexome.txt gene.txt > result.txt OFS="/t"

So, the first name in gene.txt is A2m and that does not match anything in medicalexome.txt so A2M No Match is copied to result.txt

the 213 name in gene.txt is ALK and that matches medicalexome.txt so ALK 105590 is copied to result.txt

Thank you .

Moderator's Comments:

CODE tags are needed around sample input, output, and code; not around descriptive text explaining what the tagged segments contain.

Try something like this:

Code:

awk 'FNR==NR {a[$2]=$1;next}; {b=$1; if (b in a) print $1 "\t" a[$1]; else print $1 "\t" "No Match"};' medicalexome.txt gene.txt > result.txt

@OP: Modifications to your code:

Code:

awk 'FNR==NR { E[$2]=$1 ; next } { $2=$1 in E?E[$1]:"No Match" } 1' OFS="\t" medicalexome.txt gene.txt > result.txt

Hi Scrutinizer,
Can you please educate me re: the below items in red? Why is $1 being set to $2 and what is E? doing?

Code:

awk 'FNR==NR { E[$2]=$1 ; next } { $2=$1 in E?E[$1]:"No Match" } 1' OFS="\t" medicalexome.txt gene.txt > result.txt

Hi mjf,
$2 is not being set to $1.
If $1 is present as an index in E[] ($1 in E), $2 is being set to E[$1]; otherwise $2 is being set to the string No Match.

Got it! Thanks Don. I was unfamilar with the conditional C operator.

You're welcome. condition ? TrueResult : FalseResult is a very powerful shorthand in both C and awk. Isn't this a great place to learn about the tools we all use?