How to give id to observations with the same price?

[Yuduan Pu]

Hi Folks,

I have a easy question that i hope people can help.

Here is what I have

* Example generated by -dataex-. For more info, type help dataex
clear
input byte id str9 companny
. "Google "  
. "Google "  
. "Google "  
. "Amazon"   
. "Facebook "
. "Facebook "
. "Facebook "
end

Basically, I have a bunch of company names, and I want to assign an id to companies with the same name. like all Google with id of 1, amazon with id of 2, facebook with id of 3.

The important part is, I do not want to change the order of this dataset. I tried several strategies, but they would sort my companies and list amazon at the first, because it has to sort it using alphabetic order.

Can anyone help me with that? thanks.

[Clyde Schechter]

drop id
gen `c(obs_t)' id = sum(companny != companny[_n-1])

will do it.

By the way, company is spelled with only one n.

[Yuduan Pu]

Thanks! It's very helpful.