R package_dependencies 包的依賴層次結構的計算

說明

查找(遞歸)包的依賴關係或反向依賴關係。

用法

package_dependencies(packages = NULL, db = NULL, which = "strong",
	             recursive = FALSE, reverse = FALSE,
                     verbose = getOption("verbose"))

參數

packages	包名稱的字符向量。
db	來自available.packages() 的字符矩陣(默認NULL 是此調用的結果)或其數據幀變體。或者，也可以使用 https://cran.r-project.org/web/packages/packages.rds 中提供的包數據庫。
which	列出依賴關係類型的字符向量，是 c("Depends", "Imports", "LinkingTo", "Suggests", "Enhances") 的子集。字符串 "all" 是該向量的簡寫，字符串 "most" 表示不帶 "Enhances" 的同一向量，字符串 "strong" (默認)表示該向量的前三個元素。
recursive	指示是否應包含(反向)依賴項(等等)的(反向)依賴項的邏輯，或者指示要遞歸添加的(反向)依賴項的類型的字符向量(如 which)。
reverse	邏輯：如果FALSE(默認)，則計算正則依賴關係，否則反向依賴關係。
verbose	邏輯指示輸出是否應監視包搜索周期。

值

參數 packages 中每個包都有一個元素的命名列表，每個元素都包含一個字符向量，該字符向量命名該包的(遞歸)(反向)依賴項。

對於在數據庫中找不到的給定包，將返回 NULL 條目，而不是指示沒有依賴項的 character(0) 條目。

例子

myPkgs <- c("MASS", "Matrix", "KernSmooth", "class", "cluster", "codetools")
pdb <- available.packages(repos = findCRANmirror("web"))
system.time(
dep1 <- package_dependencies(myPkgs, db = pdb) # all arguments at default
) # very fast
utils::str(dep1, vec.len=10)

system.time( ## reverse dependencies, recursively --- takes much longer:
deps <- package_dependencies(myPkgs, db = pdb, which = "most",
                             recursive = TRUE, reverse = TRUE)
) # seen ~ 10 seconds

lengths(deps) # 2020-05-03: all are 16053, but codetools with 16057

## install.packages(dependencies = TRUE) installs 'most' dependencies
## and the strong recursive dependencies of these: these dependencies
## can be obtained using 'which = "most"' and 'recursive = "strong"'.
## To illustrate on the first packages with non-missing Suggests:
packages <- pdb[head(which(!is.na(pdb[, "Suggests"]))), "Package"]
package_dependencies(packages, db = pdb,
                     which = "most", recursive = "strong")

也可以看看

dependsOnPkgs 。