哪些 R 包在附加时使用某种随机过程？

Question

这个问题的后续：

我想知道是否有一种方法可以生成所有包的列表，这些包在附加时包含某种随机过程。

Answer 1

我不知道有什么方法可以绝对确定您已经列出了详尽的清单。但是，我们可以检查您系统上所有已安装的软件包，看看它是否有 .onAttach() 或 .onLoad() 函数，如果有，它是否调用 runif() 或 sample() ，我认为这是最常见的包在附加时具有某种随机过程的情况。¹

check_packages <- function() {
    # get the names of all installed packages
    packs <- installed.packages()[ ,"Package"]
    # create an object to hold the names of packages that mess with the seed
    result <- character()
    # for each package
    for ( pack in packs ) {
        # see if it has an .onAttach or .onLoad function
        onattach <- try(getFromNamespace(".onAttach", pack), silent = TRUE)
        onload <- try(getFromNamespace(".onLoad", pack), silent = TRUE)
        # and if it does, check if it calls sample() or runif()
        if ( !inherits(onattach, "try-error") ) {
            if ( any(grepl("runif|sample", capture.output(onattach))) ) {
                # if so, add that package to the result object
                result <- c(result, pack)
                next()
            }
        }
        if ( !inherits(onload, "try-error") ) {
            if ( any(grepl("runif|sample", capture.output(onload))) ) {
                result <- c(result, pack)
                next()
            }
        }
    }
    # and return the names of all packages that do this
    return(result)
}

对我来说，结果如下：

[1] "forecast" "ggplot2"

正如我们在 to the question you linked, ggplot2 does this to randomly select tips to display to the user. As it turns out, forecast 中看到的那样：

> forecast:::.onAttach
function (...) 
{
    if (!interactive() || stats::runif(1) > 0.2) 
        return()
    tips <- c("Use suppressPackageStartupMessages() to eliminate package startup messages.", 
        "Whosebug is a great place to get help on R issues:\n  http://whosebug.com/tags/forecasting+r.", 
        "Crossvalidated is a great place to get help on forecasting issues:\n  http://stats.stackexchange.com/tags/forecasting.", 
        "Need help getting started? Try the online textbook FPP:\n  http://OTexts.org/fpp/", 
        "Want to stay up-to-date? Read the Hyndsight blog:\n  https://robjhyndman.com/hyndsight/", 
        "Want to meet other forecasters? Join the International Institute of Forecasters:\n  http://forecasters.org/")
    tip <- sample(tips, 1)
    msg <- paste("This is forecast", packageVersion("forecast"), 
        "\n ", tip)
    packageStartupMessage(msg)
}
<bytecode: 0x10e92738>
<environment: namespace:forecast>

1 _{您可以轻松调整上面 grepl() 调用中的模式，以添加调用 pseudo-random 数字生成器的任意函数。}

哪些 R 包在附加时使用某种随机过程？

Which R packages use some kind of random process when attached?

packages

r

random-seed