Through youtube, I've learned to obtain a multi-dimensional output of permutations using recursion, i.e anagrams with passing in an array of letters as an argument (i.e ['a', 'b', 'c']) but is there a way to modify the code to pass in a string instead 'abc' to obtain the output below??
Into
[ 'abc', 'bac', bca', 'acb', 'cab', 'cba' ]
This is my code. Is there a way to modify to obtain the desired result, using a string as the argument(i.e 'abc')? Thank you, much appreciated
function anagrams(inputString){
if(inputString.length ===0) return [[]];
const stringArr = inputString;
const firstEl = stringArr[0];
const restArr = stringArr.slice(1);
const anagramWithoutFirst = anagrams(restArr);
const masterArr = [];
anagramWithoutFirst.forEach(anagram => {
for (let i=0; i<=anagram.length; i++){
const anagramWithFirst = [...anagram.slice(0, i), firstEl, ...anagram.slice(i)]
masterArr.push(anagramWithFirst)
}
})
return masterArr
}
console.log(anagrams(['a', 'b', 'c']))This can be achieved using a higher order function which takes in the original function and returns a new function which splits the text up, calls the original function then joins the result back together
function anagrams(inputString){
if(inputString.length ===0) return [[]];
const stringArr = inputString;
const firstEl = stringArr[0];
const restArr = stringArr.slice(1);
const anagramWithoutFirst = anagrams(restArr);
const masterArr = [];
anagramWithoutFirst.forEach(anagram => {
for (let i=0; i<=anagram.length; i++){
const anagramWithFirst = [...anagram.slice(0, i), firstEl, ...anagram.slice(i)]
masterArr.push(anagramWithFirst)
}
})
return masterArr
}
function splitAndUnsplit(f) {
return (str) => (f(str.split('')).map(xs => xs.join('')))
}
console.log(splitAndUnsplit(anagrams)('abc'))
console.log(anagrams(['a', 'b', 'c']))Edit:
To expand on @Scott Sauyet's great comment, we need two sets of parens as we are calling two functions.
function splitAndUnsplit(f) {
return function(str){
const inputArr = str.split('')
const outputArr = f(inputArr)
const outputStr = outputArr.map(xs => xs.join('')))
return outputStr
}
}
The first set of parens is used to create a function which will accept and return a string, and the second set is required to call that function with a supplied value