First, it may be a good idea to use 1 for “yes” and 0 for “no” in the
motherrecovery column.

Then if you name your table e.g tab1,  you may try something like this..

sum(tab1[,2]==1*tab1[,4])/sum(tab1[,2]==1)

2011/12/23 Joanie Van De Walle <joanie.van-de-walle.1@ulaval.ca>

>
>   Hi,
>
>   I need help writing a function
>
>   I capture seal pups mutliple times during the lactation season in order
> to
>   monitor their growth rate. When I release them, the recovery (mother-pup)
>   time is not the same for all individuals. I want to know if individuals
> that
>   recover their mother the fastest are the ones with the highest growth
> rates.
>
>   So, I noted at every release if the pup reovered his mother before we
> leave
>   (yes or no). My dataframe looks like this
>
>   Capture nb individual individual capture motherrecovery growth rate
>   1          1          1                  n              0.5
>   2          1          2                  y              0.5
>   3          1          3                  y              0.5
>   4          1          4                  y              0.5
>   5          1          5                  n              0.5
>   6          2          1                  y              0.3
>   7          2          2                  y              0.3
>   8          3          1                  y              0.4
>   9          3          2                  n              0.4
>   10         3          3                  y              0.4
>   ...
>
>   I want to calculate a rate of mother recovery by individual, i.e. nb of
>   recoveries (y)/nb of captures. So for indivial 1 it would be 3/5 = 0.6. I
>   want  to write a function that does this for all the individuals in my
>   dataframe,  i.e. around 400 individuals (this is why I want to write a
>   function, it would be too long by hand)
>
>   Thank you,
>
>
>
>   Joanie Van de Walle
>
>   Ã‰tudiante Ã  la MaÃ®trise en Biologie
>   DÃ©partement de Biologie
>   1045, avenue de la MÃ©decine Pavillon Vachon,
>   bureau 2044 UniversitÃ© Laval
>   QuÃ©bec, Canada, G1V 0A6
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>

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