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Re: st: cumulative summation
From
James Bernard <[email protected]>
To
[email protected]
Subject
Re: st: cumulative summation
Date
Tue, 26 Feb 2013 17:03:15 +0800
Hi Nick,
Or, I am thinking about an easier option:
For me the first observation is not useful, so I want the second one
for firm A in year 1990.For firm A in year 1991, I have only one
observation and I need it. For B in year 1990 I want the observation
where ties is equal to 3. I don't want the other two cases of Firm B
in year 1990. So, I want them dropped from my dataset.
Thanks,
james
Firm Year ties
>>> ----------- ---------- -------
>>> A 1990 1
>>> A 1990 2
>>> A 1991 1
>>> B 1990 0
>>> B 1990 1
>>> B 1990 3
>>> C 1990 0
>>> C 1991 0
>>> C 1992 0
>>>
On Tue, Feb 26, 2013 at 4:39 PM, James Bernard <[email protected]> wrote:
> Thanks Nick,
>
> I have missing values in my list, so it seems that the command is not
> working, because it sets many of the values to . (missing).
>
> I gave you the simplifies version. In fact, I am using loops and
> macros to do this
>
> Then, instead would it be possible to write a comand that can detect
> that for firm A in 1990, 2 is the larger one.
>
> Alternatively, would it be possible to ask the program to keep only
> the last observation of every group (a group defined by firm and year)
>
> Thanks a gain,
> James
>
>
> On Tue, Feb 26, 2013 at 3:49 PM, Nick Cox <[email protected]> wrote:
>> bysort firm year (ties) : replace ties = ties[_N]
>>
>> Nick
>>
>> On Tue, Feb 26, 2013 at 7:08 AM, James Bernard <[email protected]> wrote:
>>
>>> I have used the sum function to calculate a variable in a panel data.
>>>
>>> Firm Year ties
>>> ----------- ---------- -------
>>> A 1990 1
>>> A 1990 2
>>> A 1991 1
>>> B 1990 0
>>> B 1990 1
>>> B 1990 3
>>> C 1990 0
>>> C 1991 0
>>> C 1992 0
>>>
>>> The issue is that the variable ties which is the number of ties a firm
>>> has formed in a year is a cumulative sum of something and, therefore,
>>> for a company like A the final number of ties in year 1990 should be
>>> 2. I need the program to write the same number (final value of the
>>> cumulative sum) instead of 1.
>> *
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