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# RE: st: add up variable / quantile

 From "Scharnigg, Stan (Stud. SBE)" <[email protected]> To "[email protected]" <[email protected]> Subject RE: st: add up variable / quantile Date Thu, 14 Apr 2011 22:55:24 +0200

```Sorry that I keep asking such simple questions, but I don't get the right outcome.
let's say that var1 has approx. 300.000 observations, and var2 approx 5000 observations.

gen var3 = var1 == var2[_n-1]
or
gen var3 = var1[_n-1] == var2

this command gives all the values of var1 a "0", and the rest a "1".

Var1 has 300.000 observations with a value, and approx 2 million with a missing value (.)
I just don't understand why Stata gives all the values of var1 a "0" and not just the values
which are the same. I tried many different, because I just want to be certain that I didn't make a
mistake, but I can't figure this out. I checked the variables and there are lots of matched values between
them.

I hope you can help me with this.

________________________________________
Van: [email protected] [[email protected]] namens Scharnigg, Stan (Stud. SBE) [[email protected]]
Verzonden: donderdag 14 april 2011 17:55
Aan: [email protected]
Onderwerp: RE: st: add up variable / quantile

aha, then is that the problem. Because var1 has 2.3 million observations and var2 has 5000 observation.
However, the values of var2 are more than once in var1.

I am gonna try this, thank you :)
________________________________________
Van: [email protected] [[email protected]] namens Nick Cox [[email protected]]
Verzonden: donderdag 14 april 2011 17:32
Aan: [email protected]
Onderwerp: Re: st: add up variable / quantile

gen var3 = var1 == var2

is certainly a good way to create a variable saying whether two
variables are the same. But what do you mean that "this is not
working"?

Note that -- necessarily -- this syntax compares values in the same
observation, and not in different observations.

gen var4 = var1 == var2[_n-1]

illustrates an extension which may be closer to what you seek.

Nick

On Thu, Apr 14, 2011 at 4:04 PM, Scharnigg, Stan (Stud. SBE)
<[email protected]> wrote:
> I tried a different approach now. I created two new variables (var1, var2), and I want to use those
> two variables to create a third variable (var3). Var3 needs to be "1" if var1 has the same values as var2
>
> So I tried this:
> gen var3 = 0
> replace var3 = 1 if var1==var2
>
> However, this is not working. Is something like this possible in Stata?
> ________________________________________
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```