How to split string into parts with N letters in each using Kotlin?-CodePudding

I need to split a string into a few parts that contain N letters each. For example

str = "Hello World! Kotlin is amazing!"
split_into_n(str, 3) = ["Hel", "lo ", "Wor", "ld!", " Ko", "tli", "n i", "s a", "maz", "ing", "!"]

I have tried regex, but it does not seem to work. I have tried using split methods but it doesn't work either. Any help would be appreciated :)

CodePudding user response：

chunked() extension function does exactly this:

val str = "Hello World! Kotlin is amazing!"
println(str.chunked(3))
// [Hel, lo , Wor, ld!,  Ko, tli, n i, s a, maz, ing, !]

CodePudding user response：

The length of the resulting array will be the length of the original array divided by N but if there is a remainder, you need an additional element.

val result=Array<String>(str.length/n (str.length%n).sign())

str.length/n is the resulting length without the last element if the original lebgth is not dividable by n.

str.length%n results in 0 if the length is dividable by n and a positive number (remainder) if it is not.

sign returns 1 if the value is positive and 0 if the value is 0.

After that, you can just fill the array with substrings:

for(i in 0..result.length){
    result[i]=str.substring(i*n,min((i 1)*n,str.length))
}

This loops over all indexes of the resulting array and sets the corresponding elements to substrings of str.

The start index is the index of the resulting array multiplied by 3 and the end index is the index before the next element (or the last total length).

Combined, it would look like this:

import kotlin.math
fun splitIntoN(str,n){
    val result=Array<String>(str.length/n (str.length%n).sign())
    for(i in 0..result.length){
        result[i]=str.substring(i*n,min((i 1)*n,str.length))
    }
}