[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]
st: RE: Check existence within a group
Your guess is right. You don't need a loop at all.
Stata is very good at doing this kind of thing
Your variable -newmkttype- is coded 0 for new, 1 for old.
Not the way that I would do it, but that's not important.
You can get it from
bysort borrower mkttype (issuedate) : gen newmkttype = _n > 1
That is we sort first on -borrower-, within -borrower- on
-mkttype-, and within -mkttype- on -issuedate-. Then you want
the first occurrence within blocks of -borrower mkttype-
to be flagged as new, by coding as 0, and later occurrences as
not new, and so coded 1. This is achieved by
_n > 1
which evaluates as 0 if _n == 1 and 1 otherwise.
de la Garza, Adrian
> I have a database that contains info on bonds issued as follows:
> borrower issuedate mtydate amount mkttype
> ABN Amro 04Jun93 03Jun98 50 E
> ABN Amro 19Sep94 17Jul96 100 E
> ABN Amro 22Nov94 21Nov98 50 S
> ACINDAR 02Feb92 30Jan99 200 L
> ACINDAR 20Mar92 19Mar97 50 E
> ACINDAR 29Jul94 28Mar00 175 L
> and I want to create a variable -newmkttype- that tells me if the
> borrower is issuing a bond in a completely new and unknown
> market type.
> If it is, then I want this variable to take the value of 0. If, on the
> contrary, the borrower has issued bonds in this market type
> in the past,
> then I want this variable to take the value of 1 (notice that the
> database is sorted by borrower issuedate mtydate amount).
> borrower issuedate mtydate amount mkttype newmkttype
> ABN Amro 04Jun93 03Jun98 50 E 0
> ABN Amro 19Sep94 17Jul96 100 E 1
> ABN Amro 22Nov94 21Nov98 50 S 0
> ACINDAR 02Feb92 30Jan99 200 L 0
> ACINDAR 20Mar92 19Mar97 50 E 0
> ACINDAR 29Jul94 28Mar00 175 L 1
> How can I construct this variable? Is there an easy way of
> checking the
> borrower's history to determine whether -newmkttype- should
> get a 0 or a
> 1, without writing a complicated loop?
* For searches and help try: