Where is dropvalue(s) mentioned? > ?subset
subset: logical expression indicating elements or rows to keep: missing values are taken as false. select: expression, indicating columns to select from a data frame. drop: passed on to ‘[’ indexing operator. ...: further arguments to be passed to or from other methods. Details: This is a generic function, with methods supplied for matrices, data frames and vectors (including lists). Packages and users can add further methods. For ordinary vectors, the result is simply ‘x[subset & !is.na(subset)]’. For data frames, the ‘subset’ argument works on the rows. Note that ‘subset’ will be evaluated in the data frame, so columns can be referred to (by name) as variables in the expression (see the examples). The ‘select’ argument exists only for the methods for data frames and matrices. It works by first replacing column names in the selection expression with the corresponding column numbers in the data frame and then using the resulting integer vector to index the columns. This allows the use of the standard indexing conventions so that for example ranges of columns can be specified easily, or single columns can be dropped (see the examples). The ‘drop’ argument is passed on to the indexing method for matrices and data frames: note that the default for matrices is different from that for indexing. Value: An object similar to ‘x’ contain just the selected elements (for a vector), rows and columns (for a matrix or data frame), and so on. Author(s): Peter Dalgaard and Brian Ripley See Also: ‘[’, ‘transform’ Examples: subset(airquality, Temp > 80, select = c(Ozone, Temp)) subset(airquality, Day == 1, select = -Temp) subset(airquality, select = Ozone:Wind) with(airquality, subset(Ozone, Temp > 80)) ## sometimes requiring a logical 'subset' argument is a nuisance nm <- rownames(state.x77) start_with_M <- nm %in% grep("^M", nm, value=TRUE) subset(state.x77, start_with_M, Illiteracy:Murder) Rich Shepard wrote: > > While reading ?subset I'm referred to learn about dropvalues() as a > following operation. Yet, when I issue ?dropvalue I see, "No documentation > for '?dropvalues' in specified packages and libraries:". > > How do I identify the library/package that contains a specific function > such as, in this case, dropvalues()? > > Rich > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- View this message in context: http://r.789695.n4.nabble.com/Identifying-Package-for-Function-tp3835227p3835252.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.