Check whether two strings are anagrams

user_13460602 0
Viewed 181

What is the most straightforward way to check whether two strings are anagrams? i.e. they share the same letters as well as number of occurrences of each these letters (and possibly other characters).

Something like this:

s1 = "elbow"
s2 = "below"

is_anagram(s1, s2)
# [1] TRUE
anagram r string
3 Answers

One way to do it is:

s1 = "elbow"
s2 = "below"

is_anagram <- function(s1, s2){
  s1_sorted <- sort(strsplit(s1, "")[[1]])
  s2_sorted <- sort(strsplit(s2, "")[[1]])
  identical(s1_sorted, s2_sorted)
}

#> is_anagram(s1, s2)
#> [1] TRUE
user_134606020

You can try the code below

> do.call(identical,Map(function(x) sort(utf8ToInt(x)), list(s1, s2)))
[1] TRUE

If you want to generalize the case to more than two strings, e.g.,

s1 <- "elbow"
s2 <- "below"
s3 <- "owlbe"

then we can try

> lst <- list(s1, s2, s3)

> all(apply(table(stack(Map(utf8ToInt, setNames(lst, seq_along(lst))))), 1, var) == 0)
[1] TRUE

or

> lst <- list(s1, s2, s3)

> m <- as.data.frame.matrix(table(stack(Map(utf8ToInt, setNames(lst, seq_along(lst))))))

> identical(do.call(pmin, m), do.call(pmax, m))
[1] TRUE
user_121587570

A simple way to achieve that:

library(tidyverse)

s1 = "elbow"
s2 = "below"

is_anagram <- function(s1, s2){
  identical(str_split(s1, "") %>% table, str_split(s2, "") %>% table)
}

is_anagram(s1, s2)

#> [1] TRUE
user_115644870
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