Sort an associative array in awk

sorting arrays awk associative

lonestar21 · Mar 16, 2010 · Viewed 32.4k times · Source

I have an associative array in awk that gets populated like this:

chr_count[$3]++

When I try to print my chr_counts, I use this:

for (i in chr_count) {
    print i,":",chr_count[i];
}

But not surprisingly, the order of i is not sorted in any way. Is there an easy way to iterate over the sorted keys of chr_count?

Answer

Instead of asort, use asorti(source, destination) which sorts the indices into a new array and you won't have to copy the array.

Then you can use the destination array as pointers into the source array.

For your example, you would use it like this:

n=asorti(chr_count, sorted)
for (i=1; i<=n; i++) {
        print sorted[i] " : " chr_count[sorted[i]]
}