regex - 有没有办法获取名称与给定正则表达式匹配的所有函数的列表？

Question

我想获得名称与给定模式匹配的所有函数的列表。例如，我想要所有名称包含“theme_”的函数。

我看过 this post它给出了获取名称向量的解决方案。是否可以使用与函数列表相同的名称而不是名称向量？

Answer 1

对于本地包你可以试试这个:

if (!require("pacman")) install.packages("pacman"); library(pacman)

regex <- "theme_"
packs <- p_lib()

out <- setNames(lapply(packs, function(x){
    funs <- try(p_funs(x, character.only=TRUE))
    if (inherits(funs, "try-error")) return(character(0))
    funs[grepl(regex, funs)]
}), packs)

out[!sapply(out, identical, character(0))]

这是我的输出:

## $cowplot
## [1] "theme_cowplot" "theme_nothing"
## 
## $ggplot2
##  [1] "theme_blank"    "theme_bw"       "theme_classic"  "theme_get"      "theme_gray"     "theme_grey"     "theme_light"    "theme_line"     "theme_linedraw" "theme_minimal" 
## [11] "theme_rect"     "theme_segment"  "theme_set"      "theme_text"     "theme_update"  
## 
## $gridExtra
## [1] "ttheme_default" "ttheme_minimal"
## 
## $plotflow
## [1] "theme_apa"   "theme_basic" "theme_black" "theme_map"  
## 
## $qdap
## [1] "theme_badkitchen" "theme_cafe"       "theme_duskheat"   "theme_grayscale"  "theme_greyscale"  "theme_hipster"    "theme_nightheat"  "theme_norah"