Identifying when a sequence stops

Question

new here so apologies if this question has been answered before. I am trying to identify a sequence within a dataset.

Example:

id	lengthofstay
1	1
1	2
1	3
2	1
2	2
3	1
3	2
3	3
3	4

Then I want to create a variable that will be 0 when the sequence is still going and 1 when the sequence ends.

E.g.

id	lengthofstay	newvariable
1	1	0
1	2	0
1	3	1
2	1	0
2	2	1
3	1	0
3	2	0
3	3	0
3	4	1

Thank you in advance for your help. Please let me know if there is anything else I can provide to be of use.

I am quite new to R so I apologize but I am at a loss to where to start. Thank you again for your help!

Answer 1

You can use ave + max

> transform(df, newvariable = +(ave(lengthofstay, id, FUN = max) == lengthofstay))
  id lengthofstay newvariable
1  1            1           0
2  1            2           0
3  1            3           1
4  2            1           0
5  2            2           1
6  3            1           0
7  3            2           0
8  3            3           0
9  3            4           1