[R] Weighting column entries in a data frame

[camillus]

Thanks!



jholtman wrote:
> 
> Try this:
> 
>> fdata
>     state statenum year    income popul
> 1 ALABAMA        1    1  9.703193  3973
> 2 ALABAMA        1    2  9.745950  3992
> 3 ALABAMA        1    3  9.762092  4015
> 4  ALASKA        2    1 10.221640   532
> 5  ALASKA        2    2 10.169600   544
> 6  ALASKA        2    3 10.101300   539
>> statepops<-tapply(fdata$popul,fdata$state,sum)
>> popweight <- statepops/sum(statepops)
>> fdata$adj <- fdata$income * popweight[fdata$state]
>> fdata
>     state statenum year    income popul      adj
> 1 ALABAMA        1    1  9.703193  3973 8.550515
> 2 ALABAMA        1    2  9.745950  3992 8.588193
> 3 ALABAMA        1    3  9.762092  4015 8.602417
> 4  ALASKA        2    1 10.221640   532 1.214266
> 5  ALASKA        2    2 10.169600   544 1.208084
> 6  ALASKA        2    3 10.101300   539 1.199971
>>
> 
> 
> On Tue, Jun 23, 2009 at 3:11 PM, camillus <citizencamillus at gmail.com>
> wrote:
> 
>>
>> Hi Guys,
>>
>> I would like to weight column entries in a data frame by the population
>> of
>> each state.  For example, here is some data:
>>
>> state     statenum year income        popul
>> ALABAMA        1    1   9.703193      3973.00
>> ALABAMA        1    2   9.745950      3992.00
>> ALABAMA        1    3   9.762092      4015.00
>> ALASKA         2    1   10.221640     532.00
>> ALASKA         2    2   10.169600     544.00
>> ALASKA         2    3   10.101300     539.00
>>
>>
>> I would like to adjust "income" by population ("popul") for each state. 
>> I
>> can use:
>>
>> statepop<-tapply(fdata$popul,fdata$state,sum),
>>
>> which gives:
>>
>> ALABAMA     ALASKA
>> 53590.130   7435.263
>>
>> I can find the weights:
>>
>> popweight <- statepops/sum(statepops)
>>
>>    ALABAMA      ALASKA
>> 0.016327564 0.002265338
>>
>> Is there an efficient way to multiply each entry of "income" by
>> "popweght"
>> conditional on the state?  That is, ALABAMA income for year 1 is
>> 9.703193*0.016327564, etc.
>>
>> Thanks,
>>
>> William
>> --
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>>
>> ______________________________________________
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>>
> 
> 
> 
> -- 
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
> 
> What is the problem that you are trying to solve?
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

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