R-devel has file_test() in utils (earlier versions had a private version in tools). That has a '-nt' op to do what you need.
file.info() accesses modification dates. Having said that, I would use 'make' as for example R's own test suites do. On Wed, 7 Feb 2007, Lutz Prechelt wrote: > Dear R-devels, > > I am looking for a package (or some other infrastructure) for the > following situation: > > I am doing a larger data evaluation. > I have several dozen data files and do not want to keep the persistent > data in the R workspace (for robustness reasons). > I have several dozen R files, some for reading and preprocessing data > files, others for doing plots or analyses. > I will make frequent changes to both data files and R files while doing > the analysis. > > I would like to automate mechanisms that allow > - a data file reading function to suppress its actual work if neither > the data file nor the R file containing the function were modified since > the data file was last read > - an R file sourcing function to suppress its actual work if the R file > has not been modified > - and perhaps even: automate re-reading a data file upon access to the > corresponding dataframe iff the file has been modified since the > dataframe was created. > > In short: Something like Unix's 'make', but for managing dependencies of > functions and dataframes in addition to files. In R. (And of course I am > very open for solutions that are more elegant than what I have sketched > above.) > > I could not find something in the help and have rather few ideas for > good search terms. > > I any such thing available? > (If no such infrastructure exists, what is the right R function for > accessing file modification dates?) > > Thanks! > > Lutz > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
