Manage the available memory in an R session

Memory is something that we always need to keep track of in R.

Here's a nice trick found in stackoverflow.com

# improved list of objects
.ls.objects <- function(pos = 1, pattern, order.by, decreasing = FALSE, head = FALSE, 
    n = 5) {
    napply <- function(names, fn) sapply(names, function(x) fn(get(x, pos = pos)))
    names <- ls(pos = pos, pattern = pattern)
    obj.class <- napply(names, function(x) as.character(class(x))[1])
    obj.mode <- napply(names, mode)
    obj.type <- ifelse(is.na(obj.class), obj.mode, obj.class)
    obj.size <- napply(names, object.size)
    obj.prettysize <- sapply(obj.size, function(r) prettyNum(r, big.mark = ","))
    obj.dim <- t(napply(names, function(x) as.numeric(dim(x))[1:2]))
    vec <- is.na(obj.dim)[, 1] & (obj.type != "function")
    obj.dim[vec, 1] <- napply(names, length)[vec]
    out <- data.frame(obj.type, obj.size, obj.prettysize, obj.dim)
    names(out) <- c("Type", "Size", "PrettySize", "Rows", "Columns")
    if (!missing(order.by)) 
        out <- out[order(out[[order.by]], decreasing = decreasing), ]
    out <- out[c("Type", "PrettySize", "Rows", "Columns")]
    names(out) <- c("Type", "Size", "Rows", "Columns")
    if (head) 
        out <- head(out, n)
    out
}

# shorthand
lsos <- function(..., n = 10) {
    .ls.objects(..., order.by = "Size", decreasing = TRUE, head = TRUE, n = n)
}

This one is going to my .Rprofile.