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Experiments with the function rapply in R's base library
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| library(magrittr) | |
| str_replace_all <- function(text, pattern, replacement){ | |
| gsub(pattern = pattern, replacement = replacement, x = text, perl = TRUE) | |
| } | |
| str_remove_all <- function(text, pattern){ | |
| str_replace_all(text, pattern = pattern, replacement = "") | |
| } | |
| pretty_str <- function(x){ | |
| capture.output(str(x)) %>% | |
| str_replace_all("\\$ :", "~") %>% | |
| str_replace_all("\\.\\.", " ") %>% | |
| str_replace_all("([[:alpha:]]+)\\s*:\\s*(.+)", "\\1: \\2") %>% | |
| str_replace_all("List of [1-9]+", "List:") %>% | |
| str_remove_all(" chr|num ") %>% | |
| str_remove_all("\\$") %>% | |
| paste(collapse = "\n") %>% | |
| cat() | |
| } | |
| my_list <- list( | |
| list(id = "a", | |
| val = 2), | |
| list(id = "b", | |
| val = 1, | |
| children = list( | |
| list(id = "b1", | |
| val = 2.5), | |
| list(id = "b2", | |
| val = 8)))) | |
| # Double all numbers | |
| my_list %>% | |
| rapply(function(x) x*2, classes = "numeric", how = "replace") %>% | |
| pretty_str() | |
| #> List: | |
| #> ~List: | |
| #> id: "a" | |
| #> val: 4 | |
| #> ~List: | |
| #> id: "b" | |
| #> val: 2 | |
| #> children: List: | |
| #> ~List: | |
| #> id: "b1" | |
| #> val: 5 | |
| #> ~List: | |
| #> id: "b2" | |
| #> val: 16 | |
| # Get all characters out and squash to flat list | |
| rapply(my_list, I, classes = "character", how = "unlist") | |
| #> id id children.id children.id | |
| #> "a" "b" "b1" "b2" | |
| my_list <- list( | |
| list(id = "hi", | |
| attribs = list( | |
| class = "a")), | |
| list(id = "there", | |
| attribs = list( | |
| class = "b")) | |
| ) | |
| extract_chr <- function(x, ...){ | |
| path_to_query <- paste(list(...), collapse = ".") | |
| flattened <- rapply(x, I, classes = "character", how = "unlist") | |
| flattened[names(flattened) == path_to_query] | |
| } | |
| extract_chr(my_list, "id") | |
| #> id id | |
| #> "hi" "there" | |
| extract_chr(my_list, "attribs", "class") | |
| #> attribs.class attribs.class | |
| #> "a" "b" |
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