Trying to solve this kata on Codewars.
I've been able to reverse the array into a string, but haven't been able to assign this string into individual elements of a specified length. I tried:
function ultimateReverse (array) {
let newArray = array.join("").split("");
let reversedArray = newArray.reverse();
return reversedArray.join("");
}
console.log(ultimateReverse(["I", "like", "big", "butts", "and", "I", "cannot", "lie!"]));
//!eiltonnacIdnasttubgibekilI
But the outcome that we want is:
["!", "eilt", "onn", "acIdn", "ast", "t", "ubgibe", "kilI"]
So according to the original array, the length of the first element should be 1, the length of the second element should be 4, the third should be length 3, and so on...
Is there a way to split a string into array of elements, each of a specified length?
I thought of creating an array of the lengths of the items from the original array by doing:
function ultimateReverse (array) {
let elementLengths = [];
let newArray = array.join("").split("");
let reversedArray = newArray.reverse().join("");
for (let i = 0; i < array.length; i++) {
let element = array[i];
elementLengths.push(element.length);
}
return reversedArray + " " + elementLengths;
}
console.log(ultimateReverse(["I", "like", "big", "butts", "and", "I", "cannot", "lie!"]));
//!eiltonnacIdnasttubgibekilI 1,4,3,5,3,1,6,4
Now if I can just split the string into elements in an array based on the length of the original elements...
The reverse() method reverses the array in place and returns the result. The original array is not mutated because we called the reverse() method on a copy of the array.
The reverse() method reverses the order of the elements in an array. The reverse() method overwrites the original array.
First construct the full reversed string, eg
!eiltonnacIdnasttubgibekilI
Then, from an array of the initial lengths (which can be done with a .map
in advance), iterate over that array and slice
that length from the reversed string, and push to an array:
function ultimateReverse(array) {
const lengths = array.map(({ length }) => length);
let reversedStr = [...array.join("")].reverse().join('');
const result = [];
lengths.forEach((length) => {
result.push(reversedStr.slice(0, length));
reversedStr = reversedStr.slice(length);
});
return result;
}
console.log(ultimateReverse(["I", "like", "big", "butts", "and", "I", "cannot", "lie!"]));
You could also keep the initial reversed data as an array that you splice
from, instead of reassigning reversedStr
:
function ultimateReverse(array) {
const lengths = array.map(({ length }) => length);
const reversedChars = [...array.join('')].reverse();
return lengths.map(
length => reversedChars.splice(0, length).join('')
);
}
console.log(ultimateReverse(["I", "like", "big", "butts", "and", "I", "cannot", "lie!"]));
You can also solve this via revering the string then mapping through it and essentially "cutting it to pieces" with substr
like this:
let reverse = arr => {
let i = 0, rData = [...arr.join('')].reverse().join('')
return arr.map(x => {
let str = rData.substr(i, x.length)
i += x.length
return str
})
}
console.log(reverse(["I", "like", "big", "butts", "and", "I", "cannot", "lie!"]))
Basically map through the original array and for each string substr
from the combined reversed string as much as the current x length is.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With