Grouping individual dates

[Scott Rick]

Hi. My data comprises several observations for each date. I want to generate a sequential numeric variable, that groups together the same date. For example, in the data below, all 22646 ==1, 22648==2, 22649==3...

I'd greatly appreciate any help in doing so.

input float appt_date
22646
22646
22646
22646
22648
22648
22648
22648
22648
22648
22649
22649
22649
22649
22649
22649
22649
22649
22650
22650
22650
22650
22650
22651
22651
22651
22651
22651
22652
22652
22652
22652
22652
22652

[Clyde Schechter]

In your example data, the observations are already sorted in appt_date order. If that is true of your full data set, then:

gen wanted = sum(appt_date != appt_date[_n-1])

If in the full data set that is not true, then the simplest way to proceed would instead be:

egen wanted = group(appt_date)

[Scott Rick]

Clyde Schechter Thanks a lot!

[Nick Cox]

Note also the label option, which is often useful.

FAQ . . . . . . . . . . . . . . . . . . . . . . Creating group identifiers

3/01 How do I create individual identifiers numbered
from 1 upwards?

https://www.stata.com/support/faqs/d...p-identifiers/