missing

[Maria Sassi]

I have a data set with the following structure

id
1
.
.
.
.
2
.
.
.
.
.
3
.
.
4
.

How can be written as
1
1
1
1
1
2
2
2
2
2
2
3
3
3
4
4
Thank you

[Clyde Schechter]

replace id = id[_n-1] if _n > 1 & missing(id)

In the future, when showing data examples, please use the -dataex- command to do so. If you are running version 16 or a fully updated version 15.1 or 14.2, -dataex- is already part of your official Stata installation. If not, run -ssc install dataex- to get it. Either way, run -help dataex- to read the simple instructions for using it. -dataex- will save you time; it is easier and quicker than typing out tables. It includes complete information about aspects of the data that are often critical to answering your question but cannot be seen from tabular displays or screenshots. It also makes it possible for those who want to help you to create a faithful representation of your example to try out their code, which in turn makes it more likely that their answer will actually work in your data.

[Maria Sassi]

Thank you for the answer