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Re: st: how do you subtract the value of one group from the value of another group?
From
Nick Cox <[email protected]>
To
"[email protected]" <[email protected]>
Subject
Re: st: how do you subtract the value of one group from the value of another group?
Date
Mon, 19 Aug 2013 21:36:48 +0100
That wasn't my suggestion, which was geared to your example with just 2 groups.
Now you tell us you have many groups. You need to tell us how
differences are defined.
Your code looks _legal_, so I don't understand the error message.
If people don't state the real problem, poor solutions are all too likely.
Nick
[email protected]
On 19 August 2013 21:05, Ken Ning <[email protected]> wrote:
> Hi Nick,
>
> Thanks a lot for this.
>
> As I have many groups， I tried this following your suggestion
>
> bysort year (id) : gen diff = value[_n] - value[_n-1]
>
>
> but it says "factor variables and time-series operators not allowed"
>
> What did i do wrong?
>
> Many thanks
> Lutao
>
>
>
> On 19 August 2013 20:43, Ken Ning <[email protected]> wrote:
>> Hi statausers
>>
>> how do you subtract the value of one group from the value of another group?
>>
>> e.g. if i want to substract the value of group 2 (value= 11 in 2001
>> and 12 in 2002) from group1 (value= 7 in 2001 and 8 in 2002) year by
>> year? so this needs to be 11-7 and 12-8 and listed next to the value
>> of group 2
>>
>>
>>
>> id year value (minus value)
>> 1 2001 7 .
>> 1 2001 7 .
>> 1 2001 7 .
>> 1 2002 8 .
>> 1 2002 8 .
>> 1 2002 8 .
>>
>> 2 2001 11 x (need to get)
>> 2 2001 11 x
>> 2 2001 11 x
>> 2 2002 12 x
>> 2 2002 12 x
>> 2 2002 12 x
>>
>> Many thanks
>> Ken
>> *
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>
> *
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*
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