Grep multiple inputs from huge file, but only the first occurance each - awk

Question

I am trying to build a "unique" zipcode list based on the data from geojson.
The goal is to grep one whole line per zip code. There are multiple entries per zipcode possible, all i care is about grabbing one per Zip.
ive prepared a "unique" zip code file to pass as grep to run as a "filter" against the list.
However, this still returns multiple results per zip code.
When limiting the results with -m 1 then i only get the very first match.
How can i filter one entry per line from the "big file"?
The input (example)
9417 TG
9423 TA
9431 HK
9883 TB
9965 TN
The command:
grep -f infile.txt bigfile.txt
the output:
9417 TG Spier Drenthe NLD Netherlands 52.8178 6.4592 ;
9423 TA Hoogersmilde Drenthe NLD Netherlands 52.9098 6.3685 ;
9417 TG Spier Drenthe NLD Netherlands 52.8178 6.4658 ;
9423 TA Hoogersmilde Drenthe NLD Netherlands 52.9066 6.3802 ;
9431 HK Westerbork Drenthe NLD Netherlands 52.8613 6.6029 ;
9431 HK Oosterwolde Friesland NLD Netherlands 52.9851 6.2986 ;
9883 TB Zuurdijk Groningen NLD Netherlands 53.3147 6.3558 ;
9965 TN Zuurdijk Groningen NLD Netherlands 53.3506 6.3691 ;
9965 TN Leens Groningen NLD Netherlands 53.3523 6.37 ;
9883 TB Oldehove Groningen NLD Netherlands 53.3108 6.3632 ;
As you can see, there are two entries for 9423 TA and 9965 TN
How can I crunch that down to one entry per list?
Thank you kindly for your help!

Answer 1

This is the job that is more suitable for awk:
awk '
NR == FNR {
zip[$1] = $2
next
}
$2 == zip[$1] {
print
delete zip[$1]
}' infile.txt bigfile.txt
9417 TG Spier Drenthe NLD Netherlands 52.8178 6.4592 ;
9423 TA Hoogersmilde Drenthe NLD Netherlands 52.9098 6.3685 ;
9431 HK Westerbork Drenthe NLD Netherlands 52.8613 6.6029 ;
9883 TB Zuurdijk Groningen NLD Netherlands 53.3147 6.3558 ;
9965 TN Zuurdijk Groningen NLD Netherlands 53.3506 6.3691 ;

Answer 2

You might use GNU AWK to deduplicate records at 1st field in bigfile.txt as follows, let bigfile.txt content be
9417 TG Spier Drenthe NLD Netherlands 52.8178 6.4592 ;
9423 TA Hoogersmilde Drenthe NLD Netherlands 52.9098 6.3685 ;
9417 TG Spier Drenthe NLD Netherlands 52.8178 6.4658 ;
9423 TA Hoogersmilde Drenthe NLD Netherlands 52.9066 6.3802 ;
9431 HK Westerbork Drenthe NLD Netherlands 52.8613 6.6029 ;
9431 HK Oosterwolde Friesland NLD Netherlands 52.9851 6.2986 ;
9883 TB Zuurdijk Groningen NLD Netherlands 53.3147 6.3558 ;
9965 TN Zuurdijk Groningen NLD Netherlands 53.3506 6.3691 ;
9965 TN Leens Groningen NLD Netherlands 53.3523 6.37 ;
9883 TB Oldehove Groningen NLD Netherlands 53.3108 6.3632
then
awk '!arr[$1]++' bigfile.txt
gives output
9417 TG Spier Drenthe NLD Netherlands 52.8178 6.4592 ;
9423 TA Hoogersmilde Drenthe NLD Netherlands 52.9098 6.3685 ;
9431 HK Westerbork Drenthe NLD Netherlands 52.8613 6.6029 ;
9883 TB Zuurdijk Groningen NLD Netherlands 53.3147 6.3558 ;
9965 TN Zuurdijk Groningen NLD Netherlands 53.3506 6.3691 ;
Explanation: ++ does return then increase by 1, arr is array (associative), if row with given 1st field was not yet encountered zero is assumed, ! is negate, therefore for each line arr[$1] is starting at 0 number of occurence of given 1st field, as this is negated, only 0 cause default action of printing, so only 1st line for each unique first column value is printed.
Use > to save effect to file e.g.
awk '!arr[$1]++' bigfile.txt > bigfileunique.txt
and then just use it in your command that is
grep -f infile.txt bigfileunique.txt
(tested in gawk 4.2.1)