How to elegantly implement such a requirement for an array?

There is an array[1,2,3,7,9,10,11,16]

Please tell me how to get it quickly and elegantly.1-3,7,9-11,16

What is the result like this?

I think this is to sort the array first and then loop to determine whether the current value is +1 from the previous one. Then splice strings based on the results. But it feels very cumbersome. I don’t know if there is any good and elegant way?

Thank you.

Reply content:

There is an array[1,2,3,7,9,10,11,16]

Please tell me how to get it quickly and elegantly.1-3,7,9-11,16

What is the result like this?

I think this is to sort the array first and then loop to determine whether the current value is +1 from the previous one. Then splice strings based on the results. But it feels very cumbersome. I don’t know if there is any good and elegant way?

Thank you.

This is the Python version (sorry, I don’t know PHP):

<code class="python">import itertools

def group_by_range(lst):
    lst.sort()
    for key, group in itertools.groupby(enumerate(lst), lambda t: t[1]-t[0]):
        rp = list(group)
        head, tail = rp[0][1], rp[-1][1]
        yield '{}-{}'.format(head, tail) if head!=tail else str(head)


if __name__ == '__main__':
    lst = [1,11,10,9,2,3,7,16]
    print(','.join(list(group_by_range(lst))))</code>

Questions I answered: Python-QA

My first thought was the same as the questioner=. =