Function to check whether two words are anagrams

is_anagram.R

# FUNCTION TO CHECK WHETHER TWO WORDS ARE ANAGRAMS

# Based on the following logic by @fermatslibrary:
# 1. Map each of the 26 English characters to a prime number
# 2. Multiply the characters of each word
# 3. Two words are anagrams if their products are the same

# This works because every integer is a prime or a unique product of primes

library(magrittr)

is_anagram <- function(word1, word2) {
  
  letters_numbers <- data.frame(letter = letters, number = primes::generate_n_primes(26))
  
  word1_split <- word1 %>% 
    tolower() %>% 
    stringr::str_remove_all(" ") %>% 
    tm::removePunctuation() %>% 
    strsplit(split = "") %>% 
    unlist() %>% 
    data.frame() %>% 
    dplyr::left_join(letters_numbers, by = c(`.` = "letter"))
  
  word2_split <- word2 %>% 
    tolower() %>% 
    stringr::str_remove_all(" ") %>% 
    tm::removePunctuation() %>% 
    strsplit(split = "") %>% 
    unlist() %>% 
    data.frame() %>% 
    dplyr::left_join(letters_numbers, by = c(`.` = "letter"))
  
  word1_prod <- prod(word1_split$number)
  word2_prod <- prod(word2_split$number)
  
  return(word1_prod == word2_prod)
    
}

is_anagram("I am Lord Voldemort", "Tom Marvolo Riddle")