Hello,
stella wrote
>
> Hi,
>
> How can a function in R handle different types of input?
> I have written a function, which should calculate the slope from several
> 3-time-point measurements by linear regression
>
> 4 three-time-point-measurements:
> x<-cbind(c(1,2,3,4),c(2,3,4,5),c(3,4,5,6))
>
> time points:
> time<-c(1,3,9)
>
> function for calculating the slope by linear regression:
> fit<-function(xx,t){slope <- coefficients(lm(log(xx) ~ 0 + t))[1]
> return(slope)
> }
> alpha<-fit(x[1,],time)
>
> At the moment the function output 'alpha' is calculated for
> x(x1=1,x2=2,x3=3). I would like to get 'alphas' for all four rows of x
> without using a for-loop. If I use 'mapply', I get outputs to very entry
> of x (12 outputs) instead of four.
>
> Thank you very much in advance! Yor help is really appreciated!
> Stella
>
It's close to what you were doing, just try
apply(x, 1, fit, time)
Hope this helps,
Rui Barradas
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