Awk create a new array of unique values from another array - awk

Question

I have my array:
array = [1:"PLCH2", 2:"PLCH1", 3:"PLCH2"]
I want to loop on array to create a new array unique of unique values and obtain:
unique = [1:"PLCH2", 2:"PLCH1"]
how can I achieve that ?
EDIT: as per #Ed Morton request, I show below how my array is populated. In fact, this post is the key solution to my previous post.
in my file.txt, I have:
PLCH2:A1007int&PLCH1:D987int&PLCH2:P977L
INTS11:P446P&INTS11:P449P&INTS11:P518P&INTS11:P547P&INTS11:P553P
I use split to obtain array:
awk '{
split($0,a,"&")
for ( i in a ) {
split(a[i], b, ":");
array[i] = b[1];
}
}' file.txt

Answer 1

This might be what you're trying to do:
$ cat tst.awk
BEGIN {
split("PLCH2 PLCH1 PLCH2",array)
printf "array ="
for (i=1; i in array; i++) {
printf " %s:\"%s\"", i, array[i]
}
print ""
for (i=1; i in array; i++) {
if ( !seen[array[i]]++ ) {
unique[++j] = array[i]
}
}
printf "unique ="
for (i=1; i in unique; i++) {
printf " %s:\"%s\"", i, unique[i]
}
print ""
}
$ awk -f tst.awk
array = 1:"PLCH2" 2:"PLCH1" 3:"PLCH2"
unique = 1:"PLCH2" 2:"PLCH1"
EDIT: given your updated question, here's how I'd really approach that:
$ cat tst.awk
BEGIN { FS="[:&]" }
{
numVals=0
for (i=1; i<NF; i+=2) {
vals[++numVals] = $i
}
print "vals =" arr2str(vals)
delete seen
numUniq=0
for (i=1; i<=numVals; i++) {
if ( !seen[vals[i]]++ ) {
uniq[++numUniq] = vals[i]
}
}
print "uniq =" arr2str(uniq)
}
function arr2str(arr, str, i) {
for (i=1; i in arr; i++) {
str = str sprintf(" %s:\"%s\"", i, arr[i])
}
return str
}
$ awk -f tst.awk file
vals = 1:"PLCH2" 2:"PLCH1" 3:"PLCH2"
uniq = 1:"PLCH2" 2:"PLCH1"
vals = 1:"INTS11" 2:"INTS11" 3:"INTS11" 4:"INTS11" 5:"INTS11"
uniq = 1:"INTS11" 2:"PLCH1"