How to group in ranges a sorted array of integers in Bash -

in bash i'have sorted integer array like:

array[0]=1 array[1]=2 array[2]=3 array[3]=4 array[4]=7 array[5]=9 array[6]=10 array[7]=13 array[8]=15 array[9]=16

and want obtain output like:

1-4,7,9-10,13,15-16

there simple , fast way it?

i don't know of standard ways of doing it, shouldn't hard write own function it. in lines of:

save first array elements 'value' 'low'
iterate on array , save current 'index' 'high'
when array 'value' differs 'index', print out 'low-high' if not 'low == high', print 'low'
reset 'low' , 'index' current 'value' , continue
increase 'index' one

should simple enough pseudo pre-sorted non-empty integer array :)

(sorry formatting, i'm on mac pc keyboard , don't along well.)

Live