[R] from 3 numeric variables to a string

Hi there, I have 3 numeric variables: day (e.g., 05), month (e.g., 06), year (e.g., 2009). I would like to create a (string) variable of the following form: month/day/year (e.g., 06/05/2009). I would be grateful to anyone who could point me toward a solution. Sincerely, Marc

[R] nlsList - Error in !unlist(lapply(coefs, is.null))

Howdee, I am able to fit a 4-parameter logistic growth curve to a dataset which comprise many individuals (using R v. 2.3.1). Yet, if I want to obtain the parameters for each individual (i.e., for each 'id') using nlsList, then I obtain an Error message which I have trouble interpreting. Any

[R] skip non-converging nls() in a list

Howdee, My question appears at #6 below: 1. I want to model the growth of each of a large number of individuals using a 4-parameter logistic growth curve. 2. nlme does not converge with the random structure that I want to use. 3. nlsList does not converge for some individuals. 4. I decided to

[R] lmList, tapply() and lm()

Howdee, *** I know that the lmList() function exists, yet I don't want to use it. *** Would anyone be kind enough to tell how I can apply the function lm() to each level of a given factor so to obtain the intercept and slope for each factor level within a matrix? For instance, suppose a

[R] number of rescaling cycles in decorana

How do one dertermine the optimal number of rescaling cycles to use when performing DCA using the decorana function (library vegan)? Thanks for your time, Marc === Marc Bélisle Professeur adjoint Chaire de recherche du Canada en écologie spatiale et en écologie du paysage