[R] matching on two criteria

[jim holtman]

You probably want something like this is there are multiple tags you
are matching on (?paste):

> TazProperties2..$Area<-TazProperties..$Area[match(
+     paste(TazProperties2..$Props2, TazProperties2..$TAZ2),
+     paste(TazProperties..$Props, TazProperties..$TAZ))]
> TazProperties2..
    Props2 TAZ2      Area
1  p754921   38 109828.04
2  p754921   37 128134.71
3  p754921   37 128134.71
4   p75506  171  37160.21
5   p75506  171  37160.21
6   p75506  282 344679.66
7   p75506  171  37160.21
8   p75508   46 342309.56
9   p75508   46 342309.56
10  p75508  169  17014.66
11  p75508  169  17014.66
12  p75508  169  17014.66
>

But even that is not sufficient since even using that, it does not
given unique values since in your first one you have multiple entries
with 'p75508 169'.  If they are the same lengths, then just copy the
data, otherwise you are going to have to add another tag to make sure
you can do a unique match.  You might try to use 'merge'.

On Tue, Feb 23, 2010 at 11:08 AM, ROLL Josh F <JRoll at lcog.org> wrote:
> Ah yes you are correct, my apologies.
> TazProperties2..$Area<-TazProperties..$Area[match(TazProperties..$Props,TazProperties..$Props)]
> should be
> TazProperties2..$Area<-TazProperties..$Area[match(TazProperties2..$Props,TazProperties..$Props)]
>
> As is this does give me what i want sort of.  The problem is it retunrs the
> same area value for all of the prop ids so i need to use a two level match
> and utilize another attribute to ensure the correct match.  Sorry for the
> sample error
>
>
> ________________________________
> From: jim holtman [mailto:jholtman at gmail.com]
> Sent: Monday, February 22, 2010 9:06 PM
> To: ROLL Josh F
> Cc: r-help at r-project.org
> Subject: Re: [R] matching on two criteria
>
> Exactly what results are you expecting?  Your 'match' has the same variables
> in both locations and will therefore return the first match:
>
>> match(TazProperties..$Props,TazProperties..$Props)
>  [1] 1 1 1 4 4 4 4 8 8 8 8 8
> so you are getting the results that you ask for.
>
> On Mon, Feb 22, 2010 at 5:42 PM, LCOG1 <jroll at lcog.org> wrote:
>>
>>
>> Howdy y'all,
>>
>> I am looking to use the match function to match a data attribute to
>> another
>> data frame but i need it to do so on two criteria to ensure an appropriate
>> match.  The following matches incorrectly.  I know the example looks
>> pointless but its just an example.  Perhaps there is another way of doing
>> this?  Thanks
>>
>> #Sample Data
>> Props<-c("p754921","p754921" ,"p754921","p75506" ,"p75506"
>>  ,"p75506","p75506"
>>  ,"p75508","p75508","p75508","p75508","p75508")
>>  TAZ<-c(38,37,37,171,171,282,171,46,46,169,169,169)
>>  Area<-c(109828.04,  128134.71,   46469.57, 37160.21,
>>  40080.50,344679.66,16972.28,
>>  342309.558, 260906.870,  17014.659,   7285.706,  10936.316)
>> #Creat 1st dataframe
>> TazProperties..<-data.frame(Props,TAZ,Area)
>>  #Sample Data
>> Props2<-c("p754921","p754921","p754921","p75506" ,"p75506"
>>  ,"p75506","p75506" ,"p75508","p75508","p75508","p75508","p75508")
>>  TAZ2<-c(38,37,37,171,171,282,171,46,46,169,169,169)
>> #Create 2nd data frame
>> TazProperties2..<-data.frame(Props2,TAZ2)
>>
>> #match on prop and return area to data frame
>>
>> TazProperties2..$Area<-TazProperties..$Area[match(TazProperties..$Props,TazProperties..$Props)]
>>
>> --
>> View this message in context:
>> http://n4.nabble.com/matching-on-two-criteria-tp1565265p1565265.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
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>> PLEASE do read the posting guide
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>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem that you are trying to solve?
>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?