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Re: st: how do you subtract the value of one group from the value of another group?
From
Ken Ning <[email protected]>
To
[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 21:05:56 +0100
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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