Remove Solar System

Excel BI’s Excel Challenge #315 — solved in R

Defining the Puzzle:

Unlike title suggests, today our task is not to manipulate planets, but to remove from our target texts all characters that are in the Solar System planets and Sun.

Remove the English letters appearing in Planets column from Author Column.

Loading Data from Excel:

Lets start loading data and libraries:

library(tidyverse)
library(readxl)
library(data.table)

planets = read_excel(“Letters Removal.xlsx”, range = “A1:A9”)
input = read_excel(“Letters Removal.xlsx”, range = “B1:B10”)
test = read_excel(“Letters Removal.xlsx”, range = “C1:C10”)

Approach 1: Tidyverse with purrr

planet_letters = planets %>% 
  mutate(planets_letters = map(Planets, ~strsplit(.x, "")) %>% flatten()) %>%
  select(-Planets) %>%
  unnest(planets_letters) %>%
  unique()

PL_upper = str_to_upper(planet_letters$planets_letters)
PL_lower = str_to_lower(planet_letters$planets_letters)
PL = c(PL_upper, PL_lower)

result = input %>%
  rowwise() %>%
  mutate(Author = str_remove_all(Author, paste0("[", paste0(PL, collapse = ""), "]")) %>% trimws()) %>%
  ungroup() %>%
  mutate(Author = if_else(str_length(Author) == 0, NA_character_, Author))

Approach 2: Base R

planet_letters <- unique(unlist(strsplit(as.character(planets$Planets), "", fixed = TRUE)))

PL_upper <- toupper(planet_letters)
PL_lower <- tolower(planet_letters)
PL <- c(PL_upper, PL_lower)

input$Author <- gsub(pattern = paste0("[", paste0(PL, collapse = ""), "]"), 
                     replacement = "", 
                     x = as.character(input$Author), 
                     perl = TRUE)

input$Author <- trimws(input$Author)
input$Author[lengths(strsplit(as.character(input$Author), NULL)) == 0] <- NA

Approach 3: Data.table

setDT(planets)
setDT(input)

planet_letters <- unique(unlist(strsplit(planets$Planets, "", fixed = TRUE)))

PL_upper <- toupper(planet_letters)
PL_lower <- tolower(planet_letters)
PL <- c(PL_upper, PL_lower)

input[, Author := gsub(pattern = paste0("[", paste0(PL, collapse = ""), "]"), 
                       replacement = "", 
                       x = Author, 
                       perl = TRUE)]

input[, Author := trimws(Author)]
input[, Author := ifelse(nchar(Author) == 0, NA_character_, Author)]

Validating Our Solutions:

identical(result$Author, test$`Answer Expected`)``
# [1] TRUE

identical(result$Author, test$`Answer Expected`)``
# [1] TRUE

identical(result$Author, test$`Answer Expected`)``
# [1] TRUE

If you like my publications or have your own ways to solve those puzzles in R, Python or whatever tool you choose, let me know.

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