Both the match() (returns the first appearance) and %in% (returns a Boolean) functions are designed for this. v <- c(‘a’,’b’,’c’,’e’) ‘b’ %in% v ## returns TRUE match(‘b’,v) ## returns the first location of ‘b’, in this case: 2
With rbind do.call(rbind.data.frame, your_list) Edit: Previous version return data.frame of list‘s instead of vectors (as @IanSudbery pointed out in comments).
Try this (see ?detach for more details): detach(“package:vegan”, unload=TRUE) It is possible to have multiple versions of a package loaded at once (for example, if you have a development version and a stable version in different libraries). To guarantee that all copies are detached, use this function. detach_package <- function(pkg, character.only = FALSE) { if(!character.only) … Read more
The R Language Definition is handy for answering these types of questions: http://cran.r-project.org/doc/manuals/R-lang.html#Indexing R has three basic indexing operators, with syntax displayed by the following examples x[i] x[i, j] x[[i]] x[[i, j]] x$a x$”a” For vectors and matrices the [[ forms are rarely used, although they have some slight semantic differences from the [ form … Read more
There’s not much of one in everyday work. However, according to the documentation for both functions (accessed by putting a ? before the function name and hitting enter), require is used inside functions, as it outputs a warning and continues if the package is not found, whereas library will throw an error.
UseMethod(“t”) is telling you that t() is a (S3) generic function that has methods for different object classes. The S3 method dispatch system For S3 classes, you can use the methods function to list the methods for a particular generic function or class. > methods(t) [1] t.data.frame t.default t.ts* Non-visible functions are asterisked > methods(class=”ts”) … Read more
lines() or points() will add to the existing graph, but will not create a new window. So you’d need to do plot(x,y1,type=”l”,col=”red”) lines(x,y2,col=”green”)
1. You can’t spell The first thing to test is have you spelled the name of the package correctly? Package names are case sensitive in R. 2. You didn’t look in the right repository Next, you should check to see if the package is available. Type setRepositories() See also ?setRepositories. To see which repositories R … Read more
See the Warning section of ?factor: In particular, as.numeric applied to a factor is meaningless, and may happen by implicit coercion. To transform a factor f to approximately its original numeric values, as.numeric(levels(f))[f] is recommended and slightly more efficient than as.numeric(as.character(f)). The FAQ on R has similar advice. Why is as.numeric(levels(f))[f] more efficent than as.numeric(as.character(f))? … Read more
You might want to consider the following package: Package xkcd: Plotting ggplot2 graphics in a XKCD style. library(xkcd) vignette(“xkcd-intro”) Some examples (Scatterplots, Bar Charts): Scatterplot: Bar Chart: