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If it’s an internal function of R (e.g. from base package), just type the function name, likeWant to share your content on R-bloggers? click here if you have a blog, or here if you don't.
> rowMeans
function (x, na.rm = FALSE, dims = 1L)
{
if (is.data.frame(x))
x <- as.matrix(x)
if (!is.array(x) || length(dn <- dim(x)) < 2L)
stop(“‘x’ must be an array of at least two dimensions”)
if (dims < 1L || dims > length(dn) – 1L)
stop(“invalid ‘dims'”)
p <- prod(dn[-(1L:dims)])
dn <- dn[1L:dims]
z <- if (is.complex(x))
.Internal(rowMeans(Re(x), prod(dn), p, na.rm)) + (0+1i) *
.Internal(rowMeans(Im(x), prod(dn), p, na.rm))
else .Internal(rowMeans(x, prod(dn), p, na.rm))
if (length(dn) > 1L) {
dim(z) <- dn
dimnames(z) <- dimnames(x)[1L:dims]
}
else names(z) <- dimnames(x)[[1L]]
z
}
<bytecode: 0x111390028>
<environment: namespace:base>
If it’s a S4 function in a package, e.g. to see the code of plotMA in the DESeq2 package, first find the object it belongs to using showMethods(), like
> showMethods(‘plotMA’)
Function: plotMA (package BiocGenerics)
object=”ANY”
object=”character”
(inherited from: object=”ANY”)
object=”DESeqDataSet”
then to get source code by getMethod(),
> getMethod(“plotMA”,”DESeqDataSet”)
Method Definition:
function (object, …)
{
.local <- function (object, lfcColname, pvalues, pvalCutoff = 0.1,
ylim, linecol = “#ff000080”, pointcol = c(“black”, “red”),
xlab, ylab, log = “x”, cex = 0.45, …)
{
if (missing(xlab))
xlab <- “mean of normalized counts”
if (missing(ylab))
ylab <- expression(log[2] ~ fold ~ change)
if (!missing(pvalues)) {
if (length(pvalues) != nrow(object)) {
stop(“length of pvalues should be equal to the number of rows of object”)
}
}
stopifnot(length(pointcol) == 2)
if (!”results” %in% mcols(mcols(object))$type) {
stop(“first run DESeq() in order to produce an MA-plot”)
}
if (missing(lfcColname)) {
lfcColname <- lastCoefName(object)
}
if (length(lfcColname) != 1 | !is.character(lfcColname)) {
stop(“the argument ‘lfcColname’ should be a character vector of length 1”)
}
if (missing(pvalues)) {
res <- results(object, name = lfcColname)
pvalues <- res$padj
}
x <- mcols(object)
stopifnot(length(cex) == 1)
col <- ifelse(is.na(pvalues) | pvalues > pvalCutoff,
pointcol[1], pointcol[2])
col = col[x$baseMean > 0]
x = x[x$baseMean > 0, ]
py = x[, lfcColname]
if (missing(ylim))
ylim = c(-1, 1) * quantile(abs(py[is.finite(py)]),
probs = 0.99) * 1.1
plot(x$baseMean, pmax(ylim[1], pmin(ylim[2], py)), log = log,
pch = ifelse(py < ylim[1], 6, ifelse(py > ylim[2],
2, 20)), cex = cex, col = col, xlab = xlab, ylab = ylab,
ylim = ylim, …)
abline(h = 0, lwd = 4, col = linecol)
}
.local(object, …)
}
<environment: namespace:DESeq2>
Signatures:
object
target “DESeqDataSet”
defined “DESeqDataSet”
Reference: http://stackoverflow.com/questions/5937832/r-show-source-code-of-an-s4-function-in-a-package
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